--- a/Makefile
+++ b/Makefile
@@ -12,8 +12,9 @@ DESTDIR =
 # This should point to the GKrellM headers
 GKRELLM_HDRS = /usr/include
 
+PKG_CONFIG ?= pkg-config
 CC = $(CC)
-GTKFLAGS := $(shell pkg-config gtk+-2.0 --cflags)
+GTKFLAGS := $(shell ${PKG_CONFIG} gtk+-2.0 --cflags)
 CFLAGS := $(CFLAGS) -fPIC $(GTKFLAGS) -I$(GKRELLM_HDRS)
 LFLAGS = -shared
 INST_DIR := $(DESTDIR)/usr/lib/gkrellm2/plugins