autoconf: Special Chars in Names
1
1 12.3 Special Characters in Make Macro Names
1 ===========================================
1
1 Posix limits macro names to nonempty strings containing only ASCII
1 letters and digits, `.', and `_'. Many `make' implementations allow a
1 wider variety of characters, but portable makefiles should avoid them.
1 It is portable to start a name with a special character, e.g.,
1 `$(.FOO)'.
1
1 Some ancient `make' implementations don't support leading
1 underscores in macro names. An example is NEWS-OS 4.2R.
1
1 $ cat Makefile
1 _am_include = #
1 _am_quote =
1 all:; @echo this is test
1 $ make
1 Make: Must be a separator on rules line 2. Stop.
1 $ cat Makefile2
1 am_include = #
1 am_quote =
1 all:; @echo this is test
1 $ make -f Makefile2
1 this is test
1
1 However, this problem is no longer of practical concern.
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