Only link with libdl on Linux

Requiring an extra library for dlopen is a Linux non-POSIX-compliance.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

programs/Makefile

@@ -17,6 +17,12 @@ LOCAL_LDFLAGS = ${MBEDTLS_TEST_OBJS} 		\
 		-lmbedx509$(SHARED_SUFFIX)	\
 		-lmbedcrypto$(SHARED_SUFFIX)
 
+ifeq ($(shell uname -s),Linux)
+DLOPEN_LDFLAGS ?= -ldl
+else
+DLOPEN_LDFLAGS ?=
+endif
+
 include ../3rdparty/Makefile.inc
 LOCAL_CFLAGS+=$(THIRDPARTY_INCLUDES)
 
@@ -354,7 +360,7 @@ test/dlopen$(EXEXT): test/dlopen.c $(DEP)
 # Do not link any test objects (that would bring in a static dependency on
 # libmbedcrypto at least). Do not link with libmbed* (that would defeat the
 # purpose of testing dynamic loading).
-	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) test/dlopen.c $(LDFLAGS) -ldl -o $@
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) test/dlopen.c $(LDFLAGS) $(DLOPEN_LDFLAGS) -o $@
 endif
 
 test/query_config.o: test/query_config.c test/query_config.h $(DEP)

programs/test/CMakeLists.txt

@@ -30,7 +30,9 @@ endif()
 if(USE_SHARED_MBEDTLS_LIBRARY)
     add_executable(dlopen "dlopen.c")
     target_include_directories(dlopen PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../../include)
-    target_link_libraries(dlopen "-ldl")
+    if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+        target_link_libraries(dlopen "-ldl")
+    endif()
 endif()
 
 if(GEN_FILES)