在Mac OS X上的Makefile中设置PATH(但它适用于Linux)

Question

我可以在Linux上的Makefile中设置PATH,但不能在Mac OS X中设置.在OS X中,PATH设置但不会被使用.这是一个演示:

在CentOS 6上使用bash 4.1.2(1)-release和GNU Make 3.81

$ pwd
/tmp/experiment
$ find * -type f -ls
132133    4 -rw-rw-r--   1 tlim tlim      113 Aug 26 11:01 Makefile
132132    4 -rwxrwxr-x   1 tlim tlim       28 Aug 26 10:59 bin/myprog
$ cat Makefile 
export PATH := $(shell /bin/pwd)/bin:$(PATH)

what:
    @echo PATH=$$PATH
    @echo PATH=$(PATH)
    which myprog
    myprog
$ cat bin/myprog 
#!/bin/bash
echo HERE I AM.
$ make what
PATH=/tmp/experiment/bin:/usr/stack/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin
PATH=/tmp/experiment/bin:/usr/stack/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin
which myprog
/tmp/experiment/bin/myprog
myprog
HERE I AM.

这是使用GNU Make 3.81在Mac OS X 10.9.4上运行的完全相同的文件:

$ pwd
/tmp/experiment
$ find * -type f -ls
51838886        8 -rw-rw-r--    1 tal              wheel                 113 Aug 26 07:01 Makefile
51838887        8 -rwxrwxr-x    1 tal              wheel                  28 Aug 26 06:59 bin/myprog
$ cat Makefile 
export PATH := $(shell /bin/pwd)/bin:$(PATH)

what:
    @echo PATH=$$PATH
    @echo PATH=$(PATH)
    which myprog
    myprog
$ cat bin/myprog 
#!/bin/bash
echo HERE I AM.
$ make what
PATH=/tmp/experiment/bin:/Users/tal/bin:/opt/local/sbin:/opt/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin
PATH=/tmp/experiment/bin:/Users/tal/bin:/opt/local/sbin:/opt/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin
which myprog
/tmp/experiment/bin/myprog
myprog
make: myprog: No such file or directory
make: *** [what] Error 1

如您所见,PATH正在设置并导出到环境中."echo $ PATH"和"my myprog"都显示路径已设置.但是,当运行"myprog"时,shell无法找到它.

更新:如果我将这两行添加到whatMakefile中的配方:

@echo SHELL=$$SHELL
@echo SHELL=$(SHELL)

Linux和Mac输出:

SHELL=/bin/bash
SHELL=/bin/sh

两者在运行之前都SHELL等于/bin/bash环境make.这让我觉得SHELL在Makefile 中设置只是神奇而且是GNU Make Manual总是设置的众多原因之一SHELL.

Answer 1

事实证明PATH变量是特殊的,除非还设置了"SHELL",否则不会导出.换句话说,如果我将这一行添加到Makefile中,它可以在Mac和Linux上运行:

SHELL=/bin/bash

当然,这让我想知道为什么Mac会有所不同.希望通过记录这一点,其他人看到这个问题也将受益.另外,我想知道为什么Mac会有所不同,如果确实如此.