diff --git a/Makefile b/Makefile
index 11cef84a..50dc1b86 100644
--- a/Makefile
+++ b/Makefile
@@ -70,7 +70,8 @@ BREW_PREFIX := $(shell brew --prefix)/opt
 CXXFLAGS += -I$(BREW_PREFIX)/readline/include
 LDFLAGS += -L$(BREW_PREFIX)/readline/lib
 
-export PKG_CONFIG_PATH := $(BREW_PREFIX)/libffi/lib/pkgconfig:$(PKG_CONFIG_PATH)
+PKG_CONFIG_PATH := $(BREW_PREFIX)/libffi/lib/pkgconfig:$(PKG_CONFIG_PATH)
+
 export PATH := $(BREW_PREFIX)/bison/bin:$(BREW_PREFIX)/gettext/bin:$(BREW_PREFIX)/flex/bin:$(PATH)
 endif
 
@@ -81,7 +82,8 @@ PORT_PREFIX := $(patsubst %/bin/port,%,$(shell which port))
 CXXFLAGS += -I$(PORT_PREFIX)/include
 LDFLAGS += -L$(PORT_PREFIX)/lib
 
-export PKG_CONFIG_PATH := $(PORT_PREFIX)/lib/pkgconfig:$(PKG_CONFIG_PATH)
+PKG_CONFIG_PATH := $(PORT_PREFIX)/lib/pkgconfig:$(PKG_CONFIG_PATH)
+
 export PATH := $(PORT_PREFIX)/bin:$(PATH)
 endif
 
@@ -224,8 +226,8 @@ endif
 endif
 
 ifeq ($(ENABLE_PLUGINS),1)
-CXXFLAGS += -DYOSYS_ENABLE_PLUGINS $(shell $(PKG_CONFIG) --silence-errors --cflags libffi)
-LDLIBS += $(shell $(PKG_CONFIG) --silence-errors --libs libffi || echo -lffi) -ldl
+CXXFLAGS += -DYOSYS_ENABLE_PLUGINS $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) $(PKG_CONFIG) --silence-errors --cflags libffi)
+LDLIBS += $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) $(PKG_CONFIG) --silence-errors --libs libffi || echo -lffi) -ldl
 endif
 
 ifeq ($(ENABLE_TCL),1)
diff --git a/README.md b/README.md
index f56bbf8c..b4b3d36e 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ Similarily, on Mac OS X MacPorts or Homebrew can be used to install dependencies
 	$ brew install bison flex gawk libffi \
 		git mercurial graphviz pkg-config python3
 	$ sudo port install bison flex readline gawk libffi \ 
-		git mercurial graphviz pkg-config python3
+		git mercurial graphviz pkgconfig python36
 
 There are also pre-compiled Yosys binary packages for Ubuntu and Win32 as well
 as a source distribution for Visual Studio. Visit the Yosys download page for