diff --git a/configure b/configure
index 5695da74..7a17b443 100755
--- a/configure
+++ b/configure
@@ -5832,23 +5832,15 @@ fi
 
 # Check whether --enable-m32 was given.
 if test "${enable_m32+set}" = set; then :
-  enableval=$enable_m32; case "${enableval}" in
-                 yes)
-                   CFLAGS="${CFLAGS} -m32"
-                   CXXFLAGS="${CXXFLAGS} -m32"
-                   usem32=true
-                   ;;
-                 no)
-                   usem32=false
-                   ;;
-                 *)
-                   as_fn_error $? "bad value ${enableval} for --enable-m32" "$LINENO" 5
-                   ;;
-               esac
+  enableval=$enable_m32;
 else
-  usem32=false
+  enable_m32=no
 fi
 
+if test "x$enable_m32" = xyes; then
+  CFLAGS="${CFLAGS} -m32"
+  CXXFLAGS="${CXXFLAGS} -m32"
+fi
 
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
@@ -7584,22 +7576,12 @@ fi
 
 # Check whether --enable-processor was given.
 if test "${enable_processor+set}" = set; then :
-  enableval=$enable_processor; case "${enableval}" in
-                 yes)
-                   disable_processor=false
-                   ;;
-                 no)
-                   disable_processor=true
-                   ;;
-                 *)
-                   as_fn_error $? "bad value ${enableval} for --disable-processor" "$LINENO" 5
-                   ;;
-               esac
+  enableval=$enable_processor;
 else
-  disable_processor=false
+  enable_processor=yes
 fi
 
- if test x$disable_processor = xtrue; then
+ if test "x$enable_processor" != xyes; then
   DISABLE_PROCESSOR_TRUE=
   DISABLE_PROCESSOR_FALSE='#'
 else
@@ -7610,22 +7592,12 @@ fi
 
 # Check whether --enable-tools was given.
 if test "${enable_tools+set}" = set; then :
-  enableval=$enable_tools; case "${enableval}" in
-                 yes)
-                   disable_tools=false
-                   ;;
-                 no)
-                   disable_tools=true
-                   ;;
-                 *)
-                   as_fn_error $? "bad value ${enableval} for --disable-tools" "$LINENO" 5
-                   ;;
-               esac
+  enableval=$enable_tools;
 else
-  disable_tools=false
+  enable_tools=yes
 fi
 
- if test x$disable_tools = xtrue; then
+ if test "x$enable_tools" != xyes; then
   DISABLE_TOOLS_TRUE=
   DISABLE_TOOLS_FALSE='#'
 else
@@ -7634,28 +7606,18 @@ else
 fi
 
 
-if test x$LINUX_HOST = xfalse -a x$disable_processor = xtrue -a x$disable_tools = xtrue; then
-   as_fn_error $? "--disable-processor and --disable-tools were specified, and not building for Linux. Nothing to build!" "$LINENO" 5
+if test x$LINUX_HOST = xfalse -a "x$enable_processor" != xyes -a "x$enable_tools" != xyes; then
+  as_fn_error $? "--disable-processor and --disable-tools were specified, and not building for Linux. Nothing to build!" "$LINENO" 5
 fi
 
 # Check whether --enable-system-test-libs was given.
 if test "${enable_system_test_libs+set}" = set; then :
-  enableval=$enable_system_test_libs; case "${enableval}" in
-                 yes)
-                   system_test_libs=true
-                   ;;
-                 no)
-                   system_test_libs=false
-                   ;;
-                 *)
-                   as_fn_error $? "bad value ${enableval} for --enable-system-test-libs" "$LINENO" 5
-                   ;;
-               esac
+  enableval=$enable_system_test_libs;
 else
-  system_test_libs=false
+  enable_system_test_libs=no
 fi
 
- if test x$system_test_libs = xtrue; then
+ if test "x$enable_system_test_libs" = xyes; then
   SYSTEM_TEST_LIBS_TRUE=
   SYSTEM_TEST_LIBS_FALSE='#'
 else
@@ -7668,7 +7630,7 @@ fi
 
 
 
-if test x$system_test_libs = xtrue; then
+if test "x$enable_system_test_libs" = xyes; then
   : "${GMOCK_CFLAGS:=-pthread}"
   : "${GMOCK_LIBS:=-lgmock -lgtest -pthread -lpthread}"
   : "${GTEST_CFLAGS:=-pthread}"
@@ -7677,22 +7639,12 @@ fi
 
 # Check whether --enable-selftest was given.
 if test "${enable_selftest+set}" = set; then :
-  enableval=$enable_selftest; case "${enableval}" in
-                 yes)
-                   selftest=true
-                   ;;
-                 no)
-                   selftest=false
-                   ;;
-                 *)
-                   as_fn_error $? "bad value ${enableval} for --enable-selftest" "$LINENO" 5
-                   ;;
-               esac
+  enableval=$enable_selftest;
 else
-  selftest=false
+  enable_selftest=no
 fi
 
- if test x$selftest = xtrue; then
+ if test "x$enable_selftest" = xyes; then
   SELFTEST_TRUE=
   SELFTEST_FALSE='#'
 else
@@ -7704,47 +7656,30 @@ fi
 
 # Check whether --with-rustc-demangle was given.
 if test "${with_rustc_demangle+set}" = set; then :
-  withval=$with_rustc_demangle; case "${withval}" in
-               yes)
-                 as_fn_error $? "You must pass the path to the rustc-demangle crate for --with-rustc-demangle" "$LINENO" 5
-                 ;;
-               no)
-                 rustc_demangle=false
-                 ;;
-               *)
-                 if ! test -f "${withval}/Cargo.toml"; then
-                   as_fn_error $? "You must pass the path to the rustc-demangle crate for --with-rustc-demangle" "$LINENO" 5
-                 fi
-                 RUSTC_DEMANGLE_CFLAGS="-DHAVE_RUSTC_DEMANGLE -I${withval}/crates/capi/include"
-                 RUSTC_DEMANGLE_LIBS="-L${withval}/target/release -lrustc_demangle -lpthread -ldl"
-                 ;;
-             esac
+  withval=$with_rustc_demangle;
 else
-  rustc_demangle=false
+  with_rustc_demangle=no
 fi
 
+if test "x${with_rustc_demangle}" != xno; then
+  if ! test -f "${with_rustc_demangle}/Cargo.toml"; then
+    as_fn_error $? "You must pass the path to the rustc-demangle crate for --with-rustc-demangle" "$LINENO" 5
+  fi
+  RUSTC_DEMANGLE_CFLAGS="-DHAVE_RUSTC_DEMANGLE -I${with_rustc_demangle}/crates/capi/include"
+  RUSTC_DEMANGLE_LIBS="-L${with_rustc_demangle}/target/release -lrustc_demangle -lpthread -ldl"
+fi
 
 
 
 
 # Check whether --with-tests-as-root was given.
 if test "${with_tests_as_root+set}" = set; then :
-  withval=$with_tests_as_root; case "${withval}" in
-               yes)
-                 tests_as_root=true
-                 ;;
-               no)
-                 tests_as_root=false
-                 ;;
-               *)
-                 as_fn_error $? "--with-tests-as-root can only be \"yes\" or \"no\"" "$LINENO" 5
-                 ;;
-             esac
+  withval=$with_tests_as_root;
 else
-  tests_as_root=false
+  with_tests_as_root=no
 fi
 
- if test x$tests_as_root = xtrue; then
+ if test "x$with_tests_as_root" = xyes; then
   TESTS_AS_ROOT_TRUE=
   TESTS_AS_ROOT_FALSE='#'
 else
diff --git a/configure.ac b/configure.ac
index 72b1bd0f..d0040723 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,21 +53,12 @@ dnl This must come before all the feature tests below.
 AC_ARG_ENABLE(m32,
               AS_HELP_STRING([--enable-m32],
                              [Compile/build with -m32]
-                             [(default is no)]),
-              [case "${enableval}" in
-                 yes)
-                   CFLAGS="${CFLAGS} -m32"
-                   CXXFLAGS="${CXXFLAGS} -m32"
-                   usem32=true
-                   ;;
-                 no)
-                   usem32=false
-                   ;;
-                 *)
-                   AC_MSG_ERROR(bad value ${enableval} for --enable-m32)
-                   ;;
-               esac],
-              [usem32=false])
+                             [(default is no)]),,
+              [enable_m32=no])
+if test "x$enable_m32" = xyes; then
+  CFLAGS="${CFLAGS} -m32"
+  CXXFLAGS="${CXXFLAGS} -m32"
+fi
 
 AC_HEADER_STDC
 AC_SYS_LARGEFILE
@@ -134,66 +125,33 @@ AM_CONDITIONAL(X86_HOST, test x$X86_HOST = xtrue)
 AC_ARG_ENABLE(processor,
               AS_HELP_STRING([--disable-processor],
                              [Don't build processor library]
-                             [(default is no)]),
-              [case "${enableval}" in
-                 yes)
-                   disable_processor=false
-                   ;;
-                 no)
-                   disable_processor=true
-                   ;;
-                 *)
-                   AC_MSG_ERROR(bad value ${enableval} for --disable-processor)
-                   ;;
-               esac],
-              [disable_processor=false])
-AM_CONDITIONAL(DISABLE_PROCESSOR, test x$disable_processor = xtrue)
+                             [(default is no)]),,
+              [enable_processor=yes])
+AM_CONDITIONAL(DISABLE_PROCESSOR, test "x$enable_processor" != xyes)
 
 AC_ARG_ENABLE(tools,
               AS_HELP_STRING([--disable-tools],
                              [Don't build tool binaries]
-                             [(default is no)]),
-              [case "${enableval}" in
-                 yes)
-                   disable_tools=false
-                   ;;
-                 no)
-                   disable_tools=true
-                   ;;
-                 *)
-                   AC_MSG_ERROR(bad value ${enableval} for --disable-tools)
-                   ;;
-               esac],
-              [disable_tools=false])
-AM_CONDITIONAL(DISABLE_TOOLS, test x$disable_tools = xtrue)
+                             [(default is no)]),,
+              [enable_tools=yes])
+AM_CONDITIONAL(DISABLE_TOOLS, test "x$enable_tools" != xyes)
 
-if test x$LINUX_HOST = xfalse -a x$disable_processor = xtrue -a x$disable_tools = xtrue; then
-   AC_MSG_ERROR([--disable-processor and --disable-tools were specified, and not building for Linux. Nothing to build!])
+if test x$LINUX_HOST = xfalse -a "x$enable_processor" != xyes -a "x$enable_tools" != xyes; then
+  AC_MSG_ERROR([--disable-processor and --disable-tools were specified, and not building for Linux. Nothing to build!])
 fi
 
 AC_ARG_ENABLE(system-test-libs,
               AS_HELP_STRING([--enable-system-test-libs],
                              [Use gtest/gmock/etc... from the system instead ]
-                             [of the local copies (default is local)]),
-              [case "${enableval}" in
-                 yes)
-                   system_test_libs=true
-                   ;;
-                 no)
-                   system_test_libs=false
-                   ;;
-                 *)
-                   AC_MSG_ERROR(bad value ${enableval} for --enable-system-test-libs)
-                   ;;
-               esac],
-              [system_test_libs=false])
-AM_CONDITIONAL(SYSTEM_TEST_LIBS, test x$system_test_libs = xtrue)
+                             [of the local copies (default is local)]),,
+              [enable_system_test_libs=no])
+AM_CONDITIONAL(SYSTEM_TEST_LIBS, test "x$enable_system_test_libs" = xyes)
 
 AC_ARG_VAR([GMOCK_CFLAGS], [Compiler flags for gmock])
 AC_ARG_VAR([GMOCK_LIBS], [Linker flags for gmock])
 AC_ARG_VAR([GTEST_CFLAGS], [Compiler flags for gtest])
 AC_ARG_VAR([GTEST_LIBS], [Linker flags for gtest])
-if test x$system_test_libs = xtrue; then
+if test "x$enable_system_test_libs" = xyes; then
   : "${GMOCK_CFLAGS:=-pthread}"
   : "${GMOCK_LIBS:=-lgmock -lgtest -pthread -lpthread}"
   : "${GTEST_CFLAGS:=-pthread}"
@@ -204,43 +162,24 @@ AC_ARG_ENABLE(selftest,
               AS_HELP_STRING([--enable-selftest],
                              [Run extra tests with "make check" ]
                              [(may conflict with optimizations) ]
-                             [(default is no)]),
-              [case "${enableval}" in
-                 yes)
-                   selftest=true
-                   ;;
-                 no)
-                   selftest=false
-                   ;;
-                 *)
-                   AC_MSG_ERROR(bad value ${enableval} for --enable-selftest)
-                   ;;
-               esac],
-              [selftest=false])
-AM_CONDITIONAL(SELFTEST, test x$selftest = xtrue)
+                             [(default is no)]),,
+              [enable_selftest=no])
+AM_CONDITIONAL(SELFTEST, test "x$enable_selftest" = xyes)
 
 AC_ARG_WITH(rustc-demangle,
             AS_HELP_STRING([--with-rustc-demangle=/path/to/rustc-demangle],
                              [Link against the rustc-demangle library]
                              [to demangle Rust language symbols during]
                              [symbol dumping (default is no)]
-                             [Pass the path to the crate root.]),
-            [case "${withval}" in
-               yes)
-                 AC_MSG_ERROR(You must pass the path to the rustc-demangle crate for --with-rustc-demangle)
-                 ;;
-               no)
-                 rustc_demangle=false
-                 ;;
-               *)
-                 if ! test -f "${withval}/Cargo.toml"; then
-                   AC_MSG_ERROR(You must pass the path to the rustc-demangle crate for --with-rustc-demangle)
-                 fi
-                 RUSTC_DEMANGLE_CFLAGS="-DHAVE_RUSTC_DEMANGLE -I${withval}/crates/capi/include"
-                 RUSTC_DEMANGLE_LIBS="-L${withval}/target/release -lrustc_demangle -lpthread -ldl"
-                 ;;
-             esac],
-            [rustc_demangle=false])
+                             [Pass the path to the crate root.]),,
+            [with_rustc_demangle=no])
+if test "x${with_rustc_demangle}" != xno; then
+  if ! test -f "${with_rustc_demangle}/Cargo.toml"; then
+    AC_MSG_ERROR(You must pass the path to the rustc-demangle crate for --with-rustc-demangle)
+  fi
+  RUSTC_DEMANGLE_CFLAGS="-DHAVE_RUSTC_DEMANGLE -I${with_rustc_demangle}/crates/capi/include"
+  RUSTC_DEMANGLE_LIBS="-L${with_rustc_demangle}/target/release -lrustc_demangle -lpthread -ldl"
+fi
 AC_ARG_VAR([RUSTC_DEMANGLE_CFLAGS], [Compiler flags for rustc-demangle])
 AC_ARG_VAR([RUSTC_DEMANGLE_LIBS], [Linker flags for rustc-demangle])
 
@@ -248,20 +187,9 @@ AC_ARG_WITH(tests-as-root,
             AS_HELP_STRING([--with-tests-as-root],
                            [Run the tests as root. Use this on platforms]
                            [like travis-ci.org that require root privileges]
-                           [to use ptrace (default is no)]),
-            [case "${withval}" in
-               yes)
-                 tests_as_root=true
-                 ;;
-               no)
-                 tests_as_root=false
-                 ;;
-               *)
-                 AC_MSG_ERROR(--with-tests-as-root can only be "yes" or "no")
-                 ;;
-             esac],
-            [tests_as_root=false])
-AM_CONDITIONAL(TESTS_AS_ROOT, test x$tests_as_root = xtrue)
+                           [to use ptrace (default is no)]),,
+            [with_tests_as_root=no])
+AM_CONDITIONAL(TESTS_AS_ROOT, test "x$with_tests_as_root" = xyes)
 
 AC_CONFIG_FILES(m4_flatten([
   breakpad.pc