use Homebrew only if installed

diff --git a/Makefile b/Makefile
index 01e1f6ad445b204d0697d3ef2213f6fde63b737e..57e935174ce81242969ae2c86ef9114a62c1e31d 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -62,15 +62,17 @@ SED = sed
 BISON = bison
 
 ifeq (Darwin,$(findstring Darwin,$(shell uname)))
+       BREW := $(shell command -v brew 2> /dev/null)
+       ifdef BREW
+               export PKG_CONFIG_PATH = $(shell $(BREW) list libffi | grep pkgconfig | xargs dirname)
+               BISON = $(shell $(BREW) list bison | grep -m1 "bin/bison")
+       endif
        # add macports/homebrew include and library path to search directories, don't use '-rdynamic' and '-lrt':
        CXXFLAGS += -I/opt/local/include -I/usr/local/opt/readline/include
        LDFLAGS += -L/opt/local/lib -L/usr/local/opt/readline/lib
-       # add homebrew's libffi include and library path
-       CXXFLAGS += $(shell PKG_CONFIG_PATH=$$(brew list libffi | grep pkgconfig | xargs dirname) pkg-config --silence-errors --cflags libffi)
-       LDFLAGS += $(shell PKG_CONFIG_PATH=$$(brew list libffi | grep pkgconfig | xargs dirname) pkg-config --silence-errors --libs libffi)
-       # use bison installed by homebrew if available
-       BISON = $(shell (brew list bison | grep -m1 "bin/bison") || echo bison)
-       SED = sed
+       # add macports/homebrew's libffi include and library path
+       CXXFLAGS += $(shell pkg-config --silence-errors --cflags libffi)
+       LDFLAGS += $(shell pkg-config --silence-errors --libs libffi)
 else
        LDFLAGS += -rdynamic
        LDLIBS += -lrt