INSTALL: diagnose missing gcc on Darwin
TBR=rsc
https://codereview.appspot.com/55700043
diff --git a/INSTALL b/INSTALL
index 8bc208b..9c5592e 100755
--- a/INSTALL
+++ b/INSTALL
@@ -76,7 +76,11 @@
# On Darwin, uname -m -p cannot be trusted.
echo "* Running on Darwin: checking architecture..."
rm -f ./a.out
- gcc lib/darwin-main.c >/dev/null 2>&1
+ if ! gcc lib/darwin-main.c >/dev/null 2>&1; then
+ echo "Cannot find gcc. You may need to install the command-line tools using Xcode." >&2
+ echo "See http://swtch.com/go/xcodegcc for details." >&2
+ exit 1
+ fi
case "$(file ./a.out 2>/dev/null)" in
*x86_64*)
echo " x86-64 found."
