--- a/dev-db/firebird/files/firebird-2.5.7.27050.0-gcc6.patch	
+++ a/dev-db/firebird/files/firebird-2.5.7.27050.0-gcc6.patch	
@@ -32,4 +32,37 @@ PR: https://github.com/FirebirdSQL/firebird/pull/104
 +		static_cast<SCHAR>(blr_end),
  		blr_eoc
  	};
- 	static FB_API_HANDLE req_handle;
+ 	static FB_API_HANDLE req_handle;
+--- a/src/include/fb_blk.h	2017-12-04 15:52:55.975910661 +0100
@@ -88,6 +88,7 @@ src_prepare() {
 src_configure() {
 	filter-flags -fprefetch-loop-arrays
 	filter-mfpmath sse
+	append-cxxflags -flifetime-dse=1 -fno-sized-deallocation -fno-delete-null-pointer-checks
 
 	econf \
 		--prefix=/usr/$(get_libdir)/firebird \