Hello list,

I happen to own a Mac M1 for $DAYJOB. I tried to build got in there with
no success, as configure uses some hardcoded paths in /usr/local that
correspond to Homebrew packages. Somewhere along the path, Homebrew
changed the default installation path from /usr/local to /opt/homebrew.
Instead of trying to guess, given that Homebrew does recommend running
`brew shellenv` in your shell rc file, check and use for the existence
of HOMEBREW_PREFIX in the environment, and default to /usr/local if it's
not the case. With this, I'm able to build and run got in my Mac M1.

-Lucas


diff --git a/configure.ac b/configure.ac
index 554ab266..7a742348 100644
--- a/configure.ac
+++ b/configure.ac
@@ -228,16 +228,17 @@ AM_CONDITIONAL([HOST_NETBSD], [test "$PLATFORM" = "netbsd"])
 AM_CONDITIONAL([HOST_DRAGONFLYBSD], [test "$PLATFORM" = "dragonflybsd"])
 
 if test x"$PLATFORM" = "xdarwin"; then
-	if ! test -x "/usr/local/opt/bison/bin/bison"; then
+	: ${HOMEBREW_PREFIX:=/usr/local}
+	if ! test -x "$HOMEBREW_PREFIX/opt/bison/bin/bison"; then
 		AC_MSG_ERROR("GNU Bison not found")
 	fi
 
 	# Override YACC here to point to the GNU version of bison.
-	export YACC="/usr/local/opt/bison/bin/bison -y"
-	export LDFLAGS="-L/usr/local/opt/ncurses/lib -L/usr/local/opt/openssl@3/lib $LDFLAGS"
-	export CPPFLAGS="-I/usr/local/opt/ncurses/include -I/usr/local/opt/openssl@3/include $CPPFLAGS"
-	export PKG_CONFIG_PATH="/usr/local/opt/ncurses/lib/pkgconfig"
-	export PKG_CONFIG_PATH="$PKG_CONFIG_PATH:/usr/local/opt/openssl@3/lib/pkgconfig"
+	export YACC="$HOMEBREW_PREFIX/opt/bison/bin/bison -y"
+	export LDFLAGS="-L$HOMEBREW_PREFIX/opt/ncurses/lib -L$HOMEBREW_PREFIX/opt/openssl@3/lib $LDFLAGS"
+	export CPPFLAGS="-I$HOMEBREW_PREFIX/opt/ncurses/include -I$HOMEBREW_PREFIX/opt/openssl@3/include $CPPFLAGS"
+	export PKG_CONFIG_PATH="$HOMEBREW_PREFIX/opt/ncurses/lib/pkgconfig"
+	export PKG_CONFIG_PATH="$PKG_CONFIG_PATH:$HOMEBREW_PREFIX/opt/openssl@3/lib/pkgconfig"
 fi
 
 # Landlock detection.