Makefile: detect new Homebrew location for ARM-based Macs

With the introduction of the ARM-based Macs the default location for
Homebrew has changed from "/usr/local" to "/opt/homebrew". We only
handle the former location though, which means that unless the user has
manually configured required search paths we won't be able to locate it.

Improve upon this by adding relevant paths to our CFLAGS and LDFLAGS as
well as detecting the location of msgfmt(1).

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

config.mak.uname

@@ -158,6 +158,19 @@ ifeq ($(uname_S),Darwin)
 		ifeq ($(shell test -x /usr/local/opt/gettext/bin/msgfmt && echo y),y)
 			MSGFMT = /usr/local/opt/gettext/bin/msgfmt
 		endif
+	# On newer ARM-based machines the default installation path has changed to
+	# /opt/homebrew. Include it in our search paths so that the user does not
+	# have to configure this manually.
+	#
+	# Note that we do not employ the same workaround as above where we manually
+	# add gettext. The issue was fixed more than three years ago by now, and at
+	# that point there haven't been any ARM-based Macs yet.
+	else ifeq ($(shell test -d /opt/homebrew/ && echo y),y)
+		BASIC_CFLAGS += -I/opt/homebrew/include
+		BASIC_LDFLAGS += -L/opt/homebrew/lib
+		ifeq ($(shell test -x /opt/homebrew/bin/msgfmt && echo y),y)
+			MSGFMT = /opt/homebrew/bin/msgfmt
+		endif
 	endif
 
 	# The builtin FSMonitor on MacOS builds upon Simple-IPC.  Both require