Add automatic memmem detction instead of the previous hack

CMakeLists.txt

@@ -26,6 +26,11 @@ find_package(Git)
 find_package(Sqlite3)
 
 include(TestBigEndian)
+include(CheckSymbolExists) 
+
+#Some functions need this to be found
+add_definitions(-D_GNU_SOURCE)
+set(CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS} -D_GNU_SOURCE")
 
 TEST_BIG_ENDIAN(BIGENDIAN)
 if (BIGENDIAN)
@@ -57,6 +62,8 @@ if (MSVC)
 	add_definitions(-D_CRT_SECURE_NO_WARNINGS)
 endif()
 
+check_symbol_exists(memmem string.h HAVE_MEMMEM)
+
 include_directories("${PROJECT_SOURCE_DIR}")
 include_directories(${SQLITE3_INCLUDE_DIRS})
 link_directories(${SQLITE3_LIBRARY_DIRS})

src/system.h.in

@@ -84,11 +84,9 @@
 #define HAVE_GETOPT
 #define HAVE_SSIZE_T
 #include <dlfcn.h>
-#ifndef __HAIKU__
-#define HAVE_MEMMEM
-#endif
 #define HAVE_GETRLIMIT
 #endif
+#cmakedefine HAVE_MEMMEM
 
 /* printf support for size_t and uint64_t */
 #if defined(WIN32)
@@ -140,7 +138,6 @@
 
 #if ( defined(BSD_LIKE) && !defined(__FreeBSD_kernel__) ) || defined(__sun__)
 #undef HAVE_STRNDUP
-#undef HAVE_MEMMEM
 #endif
 
 #ifdef HAVE_GETOPT