Issue #10651 has been reported by Anatol Pomozov.

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Bug #10651: pkg_config does not report required include headers
https://bugs.ruby-lang.org/issues/10651

* Author: Anatol Pomozov
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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pkg_config behavior seems incorrect in 2.2.0. I am testing following script in Linux Arch:

`require 'mkmf'
puts pkg_config("xft")`

In 2.1.5 it gives
`["-I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz", "", "-lXft"]`

In 2.2.0 it gives
`["", "", "-lXft"]`

pkg-config command line tool gives.

`$ pkg-config --cflags xft
-I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz`

So it points that new pkg_config implementation is incorrect.


Here is content of the pc file itself:

$ cat /usr/lib/pkgconfig/xft.pc 
prefix=/usr
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: Xft
Description: X FreeType library
Version: 2.3.2
Requires: xproto
Requires.private: xrender, fontconfig, freetype2
Cflags: -I${includedir}
Libs: -L${libdir} -lXft



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