Update

src/inotail/Makefile

 BINDIR	= $(prefix)/bin
 MANDIR	= $(prefix)/share/man/man1
 
-CC	:= gcc
-CFLAGS	:= $(CFLAGS) -pipe -D_USE_SOURCE -DVERSION="\"$(VERSION)\"" -W -Wall \
+CC	   ?= gcc
+CFLAGS := $(CFLAGS) -pipe -D_USE_SOURCE -DVERSION="\"$(VERSION)\"" -W -Wall \
 	   -Wstrict-prototypes -Wsign-compare -Wshadow -Wchar-subscripts \
 	   -Wmissing-declarations -Wpointer-arith -Wcast-align -Wmissing-prototypes