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Diffstat (limited to 'm4/ax_extend_srcdir.m4')
| -rw-r--r-- | m4/ax_extend_srcdir.m4 | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/m4/ax_extend_srcdir.m4 b/m4/ax_extend_srcdir.m4 new file mode 100644 index 0000000..40f3787 --- /dev/null +++ b/m4/ax_extend_srcdir.m4 @@ -0,0 +1,86 @@ +# =========================================================================== +# http://www.gnu.org/software/autoconf-archive/ax_extend_srcdir.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_EXTEND_SRCDIR +# +# DESCRIPTION +# +# The AX_EXTEND_SRCDIR macro extends $srcdir by one path component. +# +# As an example, when working in /home/michael/i3-4.12/build and calling +# ../configure, your $srcdir is "..". After calling AX_EXTEND_SRCDIR, +# $srcdir will be set to "../../i3-4.12". +# +# The result of extending $srcdir is that filenames (e.g. in the output of +# the "backtrace" gdb command) will include one more path component of the +# absolute source path. The additional path component makes it easy for +# users to recognize which files belong to the PACKAGE, and -- provided a +# dist tarball was unpacked -- which version of PACKAGE was used. +# +# As an example, in "backtrace", you will see: +# +# #0 main (argc=1, argv=0x7fffffff1fc8) at ../../i3-4.12/src/main.c:187 +# +# instead of: +# +# #0 main (argc=1, argv=0x7fffffff1fc8) at ../src/main.c:187 +# +# In case your code uses the __FILE__ preprocessor directive to refer to +# the filename of the current source file (e.g. in debug messages), using +# the extended path might be undesirable. For this purpose, +# AX_EXTEND_SRCDIR defines the output variable AX_EXTEND_SRCDIR_CPPFLAGS, +# which can be added to AM_CPPFLAGS in Makefile.am in order to define the +# preprocessor directive STRIPPED__FILE__. As an example, when compiling +# the file "../../i3-4.12/src/main.c", STRIPPED__FILE__ evaluates to +# "main.c". +# +# There are some caveats: When $srcdir is "." (i.e. when ./configure was +# called instead of ../configure in a separate build directory), +# AX_EXTEND_SRCDIR will still extend $srcdir, but the intended effect will +# not be achieved because of the way automake specifies file paths: +# automake defines COMPILE to use "`test -f '$source' || echo +# '\$(srcdir)/'`$source" in order to prefer files in the current directory +# over specifying $srcdir explicitly. +# +# The AX_EXTEND_SRCDIR author is not aware of any way to influence this +# automake behavior. Patches very welcome. +# +# To work around this issue, you can use AX_ENABLE_BUILDDIR i.e. by adding +# the following code to configure.ac: +# +# AX_ENABLE_BUILDDIR +# dnl ... +# AX_EXTEND_SRCDIR +# +# Then also add this bit to Makefile.am (if you wish to use +# STRIPPED__FILE__ in your code): +# +# AM_CPPFLAGS = @AX_EXTEND_SRCDIR_CPPFLAGS@ +# +# LICENSE +# +# Copyright (c) 2016 Michael Stapelberg <michael@i3wm.org> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 3 + +AC_DEFUN([AX_EXTEND_SRCDIR], +[dnl +AS_CASE([$srcdir], + [.|.*|/*], + [ + # pwd -P is specified in IEEE 1003.1 from 2004 + as_dir=`cd "$srcdir" && pwd -P` + as_base=`AS_BASENAME([$as_dir])` + srcdir=${srcdir}/../${as_base} + + AC_SUBST([AX_EXTEND_SRCDIR_CPPFLAGS], ["-DSTRIPPED__FILE__=AS_ESCAPE([\"$$(basename $<)\"])"]) + ]) +])dnl AX_EXTEND_SRCDIR |