diff -Naur free42-nologo-2.5.12.orig/gtk/Makefile free42-nologo-2.5.12/gtk/Makefile
--- free42-nologo-2.5.12.orig/gtk/Makefile	2019-11-28 20:11:51.000000000 +0100
+++ free42-nologo-2.5.12/gtk/Makefile	2019-11-29 17:59:58.292516949 +0100
@@ -15,7 +15,7 @@
 # along with this program; if not, see http://www.gnu.org/licenses/.
 ###############################################################################
 
-CFLAGS = -MMD \
+CFLAGS := -MMD \
 	 -Wall \
 	 -Wno-parentheses \
 	 -Wno-write-strings \
@@ -34,7 +34,8 @@
 	 -DDECIMAL_GLOBAL_ROUNDING=1 \
 	 -DDECIMAL_GLOBAL_ROUNDING_ACCESS_FUNCTIONS=1 \
 	 -DDECIMAL_GLOBAL_EXCEPTION_FLAGS=1 \
-	 -DDECIMAL_GLOBAL_EXCEPTION_FLAGS_ACCESS_FUNCTIONS=1
+	 -DDECIMAL_GLOBAL_EXCEPTION_FLAGS_ACCESS_FUNCTIONS=1 \
+	 ${CFLAGS}
 
 ###############################################################################
 ### Note that there are deprecation warnings while compiling shell_main.cc  ###
@@ -46,10 +47,11 @@
 ### GTK+ 3.22 for testing.                                                  ###
 ###############################################################################
 
-CXXFLAGS = $(CFLAGS) \
+CXXFLAGS := $(CFLAGS) \
 	 -fno-exceptions \
 	 -fno-rtti \
-	 -D_WCHAR_T_DEFINED
+	 -D_WCHAR_T_DEFINED \
+	 ${CFLAGS}
 
 LIBS = gcc111libbid.a $(shell pkg-config --libs gtk+-3.0)
 
@@ -125,7 +127,7 @@
 
 symlinks:
 	for fn in `cd ../common; /bin/ls`; do ln -s ../common/$$fn; done
-	sh ./build-intel-lib.sh
+	+sh ./build-intel-lib.sh
 	ln -s IntelRDFPMathLib20U1/TESTS/readtest.c
 	touch symlinks
 
