diff --git a/Makefile.in b/Makefile.in
index aeabdc2..376670d 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -54,14 +54,11 @@ endif
 # default is. The -with-abi is not necessary for this project. Unconditionally
 # compile it with a no-float ABI. i.e., ilp32 for 32-bit and lp64 for 64-bit.
 
-ifeq (@WITH_ARCH@,)
-  march := -march=$(shell @CC@ -v 2>&1 | \
-                    sed 's/ /\n/g' | grep with-arch | awk -F= '{print $$2}')
-else
+ifneq (@WITH_ARCH@,)
   march := -march=@WITH_ARCH@
+  is_32bit := $(findstring 32,$(march))
+  mabi := -mabi=$(if $(is_32bit),ilp32,lp64)
 endif
-is_32bit := $(findstring 32,$(march))
-mabi := -mabi=$(if $(is_32bit),ilp32,lp64)
 
 # Installation directories