firebird: adapt asan.patch to GCC, which lacks __has_feature

Also apply sanitizer.patch, because why not.

Also tweak configure to check for dlsym() instead of dlopen();
the situation described in commit
037584cf still holds on Fedora 27.

Change-Id: I446fa3e991aec06452f135ab8365702a397c441a
Reviewed-on: https://gerrit.libreoffice.org/55247Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>

external/firebird/UnpackedTarball_firebird.mk

@@ -48,12 +48,10 @@ $(eval $(call gb_UnpackedTarball_add_patches,firebird,\
 ))
 endif
 
-ifeq ($(COM_IS_CLANG),TRUE)
 ifneq ($(filter -fsanitize=%,$(CC)),)
 $(eval $(call gb_UnpackedTarball_add_patches,firebird, \
     external/firebird/sanitizer.patch \
 ))
 endif
-endif
 
 # vim: set noet sw=4 ts=4:

external/firebird/asan.patch

@@ -204,7 +204,7 @@
  #ifdef DEBUG_GDS_ALLOC
 --- src/include/firebird.h
 +++ src/include/firebird.h
-@@ -38,8 +38,17 @@
+@@ -38,8 +38,20 @@
  #include "gen/autoconfig.h"
  #endif
  
@@ -216,6 +216,9 @@
 +#if defined __clang__ && (defined __apple_build_version__ ? __clang_major__ >= 9 : __clang_major__ >= 4)
 +#define USE_ASAN
 +#endif
++#if defined __SANITIZE_ADDRESS__
++#define USE_ASAN
++#endif
 +
  // Using our debugging code is pointless when we may use Valgrind features
 -#if defined(DEV_BUILD) && !defined(USE_VALGRIND)
@@ -234,3 +237,19 @@
  			T* end;
  		};
  #endif	// RECURSIVE_SIMILAR
+--- configure.orig	2018-06-03 17:44:50.152951348 +0200
++++ configure	2018-06-03 17:45:11.708907807 +0200
+@@ -18479,11 +18479,11 @@
+ #ifdef __cplusplus
+ extern "C"
+ #endif
+-char dlopen ();
++char dlsym ();
+ int
+ main ()
+ {
+-return dlopen ();
++return dlsym ();
+   ;
+   return 0;
+ }