build: install libpkgconf .pc file

Makefile.am

@@ -4,9 +4,11 @@ datadir                = @datadir@
 includedir             = @includedir@
 system_includedir      = @SYSTEM_INCLUDEDIR@
 system_libdir          = @SYSTEM_LIBDIR@
-pkgconfigdir           = @PKGCONFIGDIR@
+pkg_default_dir        = @PKGCONFIGDIR@
+pkgconfigdir           = $(libdir)/pkgconfig
+nodist_pkgconfig_DATA  = libpkgconf.pc
 
-AM_CFLAGS = -Wall -Wextra -Wformat=2 -std=gnu99 -DPKG_DEFAULT_PATH=\"$(pkgconfigdir)\" -DSYSTEM_INCLUDEDIR=\"$(system_includedir)\" -DSYSTEM_LIBDIR=\"$(system_libdir)\"
+AM_CFLAGS = -Wall -Wextra -Wformat=2 -std=gnu99 -DPKG_DEFAULT_PATH=\"$(pkg_default_dir)\" -DSYSTEM_INCLUDEDIR=\"$(system_includedir)\" -DSYSTEM_LIBDIR=\"$(system_libdir)\"
 
 bin_PROGRAMS = pkgconf
 lib_LTLIBRARIES = libpkgconf.la

configure.ac

@@ -45,5 +45,5 @@ AC_PROG_CC
 AC_PROG_INSTALL
 AC_PROG_LN_S
 
-AC_CONFIG_FILES([Makefile Kyuafile tests/Kyuafile tests/test_env.sh])
+AC_CONFIG_FILES([Makefile Kyuafile libpkgconf.pc tests/Kyuafile tests/test_env.sh])
 AC_OUTPUT

libpkgconf.pc.in

@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=${prefix}
+includedir=@includedir@
+libdir=@libdir@
+
+Name: libpkgconf
+Description: a library for accessing and manipulating development framework configuration
+URL: http://github.com/pkgconf/pkgconf
+Version: @PACKAGE_VERSION@
+CFlags: -I${includedir}/pkgconf
+Libs: -L${libdir} -lpkgconf