diff --git a/lisp/Config.linux_gencgc b/lisp/Config.linux_gencgc
index 6c5cadf415eb1574ec88156aca818b4518af22b6..0b6f2a171fbbbc3c5bb2fca48e771bc60e1271e9 100644
--- a/lisp/Config.linux_gencgc
+++ b/lisp/Config.linux_gencgc
@@ -20,7 +20,11 @@ endif
 
 RUNTIME = $(GENCGC) $(LINKAGE)
 # __NO_CTYPE so builds on glibc 2.3 will run on (some) older glibc's.
+ifneq (,$(filter 2% 3%, $(shell $(CC) -dumpversion)))
 CPPFLAGS = -D__NO_CTYPE -D_GNU_SOURCE -I. -I$(PATH1) -I- $(RUNTIME)
+else
+CPPFLAGS = -D__NO_CTYPE -D_GNU_SOURCE -iquote. -iquote $(PATH1) $(RUNTIME)
+endif
 
 CFLAGS = -rdynamic -Wstrict-prototypes -Wall -O2 -g $(RUNTIME)
 ASFLAGS = -g $(GENCGC) $(LINKAGE_TABLE)