Respect user's pkg-config, don't call gcc directly, respect CFLAGS
--- a/Makefile
+++ b/Makefile
@@ -8,14 +8,14 @@ LFLAGS += $(LDFLAGS)
 
 ## Support for GKrellM 2.0
 #
-GTK2_INCLUDE = `pkg-config gtk+-2.0 --cflags`
-GTK2_LIB = `pkg-config gtk+-2.0 --libs`
+PKG_CONFIG ?= pkg-config
+GTK2_INCLUDE = $(shell ${PKG_CONFIG} gtk+-2.0 --cflags)
+GTK2_LIB = $(shell ${PKG_CONFIG} gtk+-2.0 --libs)
 SINSTALLDIR2 = /usr/share/gkrellm2/plugins
 UINSTALLDIR2 = $(HOME)/.gkrellm2/plugins
-FLAGS2 = -O2 -Wall -fPIC -I. $(GTK2_INCLUDE)
+FLAGS2 = -fPIC -I. $(GTK2_INCLUDE)
 LIBS2 = $(GTK2_LIB)
-CC2 = gcc $(FLAGS2) -DGKRELLM2
-CC2F = gcc $(FLAGS2) -DFAKE -DGKRELLM2
+CC = $(CC)
 OBJS2 = i8krellm.o
 
 # seems to barf without the @echo....
@@ -23,14 +23,14 @@ i8krellm: i8krellm.so
 	@echo ""
 
 i8krellm.so: $(OBJS2)
-	$(CC2) $(OBJS2) -o i8krellm.so $(LFLAGS) $(LIBS2)
+	$(CC) $(CFLAGS) $(CFLAGS) $(FLAGS2) -DGKRELLM2 $(OBJS2) -o i8krellm.so $(LFLAGS) $(LIBS2)
 
 fake: i8krellm.c prop-anim.xpm
-	$(CC2F) -c -o i8krellm.o i8krellm.c
-	$(CC2F) $(OBJS2) -o i8krellm.so $(LFLAGS) $(LIBS2)
+	$(CC) $(CFLAGS) $(FLAGS2) -DFAKE -DGKRELLM2 -c -o i8krellm.o i8krellm.c
+	$(CC) $(CFLAGS) $(FLAGS2) -DFAKE -DGKRELLM2 $(OBJS2) -o i8krellm.so $(LFLAGS) $(LIBS2)
 
 i8krellm.o: i8krellm.c prop-anim.xpm
-	$(CC2) -c -o i8krellm.o i8krellm.c
+	$(CC) $(CFLAGS) $(FLAGS2) -DGKRELLM2 -c -o i8krellm.o i8krellm.c
 
 site_install: i8krellm.so
 	install -c -s -m 644 i8krellm.so $(SINSTALLDIR2)