Use portable suffix rules and use .cc

build/build.mk

@@ -1,6 +1,9 @@
 depcomp = /bin/sh $(top_srcdir)/build/autotools/depcomp
 
-%.o: %.cpp $(top_srcdir)/src/stringfix
+.SUFFIXES:
+.SUFFIXES: .c .cc .h .o
+
+.cc.o: $(top_srcdir)/src/stringfix
 	@echo -e "[CC]	\033[1m$*\033[0m"
 	trap "rm -f '.deps/$*.Tpo' $*.ii; exit 1" 1 2 3 5 10 13 15; \
 	if [ "$(CCDEPMODE)" = "gcc3" ]; then \
@@ -14,7 +17,7 @@ depcomp = /bin/sh $(top_srcdir)/build/autotools/depcomp
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c $*.ii -o $@; \
 	rm -f '.deps/$*.Tpo' $*.ii
 
-%.o: %.c $(top_srcdir)/src/stringfix
+.c.o: $(top_srcdir)/src/stringfix
 	@echo -e "[C ]	\033[1m$*\033[0m"
 	trap "rm -f '.deps/$*.Tpo' $*.i; exit 1" 1 2 3 5 10 13 15; \
 	if [ "$(CCDEPMODE)" = "gcc3" ]; then \