From: Emily <vcs@emily.moe>
Date: Wed, 4 Sep 2019 23:30:29 +0000 (+0100)
Subject: Use $(shell :; ...) in Makefile to force shell
X-Git-Tag: working-ls180~1075^2~4^2
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a9af28694ce5fbcf4cdfd0c3cb440c08681f8f16;p=yosys.git

Use $(shell :; ...) in Makefile to force shell

Did you think that `$(shell command -v ...)` would actually get run by
the shell? Foolish mortal; GNU Make is obviously far more wise than
thee, as it optimizes it to a direct -- and hence broken (since
`command` is a shell builtin) -- exec. This horrifying contortion
ensures that an actual shell runs the command and fixes the behaviour.

@Shizmob found the source of this misbehaviour; turns out gmake has a
hard-coded, incomplete list of shell builtins:

    https://github.com/mirror/make/blob/715c787dc69bac37827a7d6ea6d40a86c55b5583/src/job.c#L2691

This contains `command`, but the whole function is full of horrible
heuristic garbage so who knows. I'm so sorry.
---

diff --git a/Makefile b/Makefile
index bb26eabed..8e01ac137 100644
--- a/Makefile
+++ b/Makefile
@@ -88,7 +88,7 @@ ifeq ($(OS), Darwin)
 PLUGIN_LDFLAGS += -undefined dynamic_lookup
 
 # homebrew search paths
-ifneq ($(shell command -v brew),)
+ifneq ($(shell :; command -v brew),)
 BREW_PREFIX := $(shell brew --prefix)/opt
 $(info $$BREW_PREFIX is [${BREW_PREFIX}])
 ifeq ($(ENABLE_PYOSYS),1)
@@ -102,8 +102,8 @@ PKG_CONFIG_PATH := $(BREW_PREFIX)/tcl-tk/lib/pkgconfig:$(PKG_CONFIG_PATH)
 export PATH := $(BREW_PREFIX)/bison/bin:$(BREW_PREFIX)/gettext/bin:$(BREW_PREFIX)/flex/bin:$(PATH)
 
 # macports search paths
-else ifneq ($(shell command -v port),)
-PORT_PREFIX := $(patsubst %/bin/port,%,$(shell command -v port))
+else ifneq ($(shell :; command -v port),)
+PORT_PREFIX := $(patsubst %/bin/port,%,$(shell :; command -v port))
 CXXFLAGS += -I$(PORT_PREFIX)/include
 LDFLAGS += -L$(PORT_PREFIX)/lib
 PKG_CONFIG_PATH := $(PORT_PREFIX)/lib/pkgconfig:$(PKG_CONFIG_PATH)