Install .pc file to /usr/share instead of /usr/lib because there are no .so files

--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,6 @@
 AUTOMAKE_OPTIONS = foreign dist-bzip2 dist-zip
 
-pkgconfig_DATA = asio.pc
-pkgconfigdir = $(libdir)/pkgconfig
+noarch_pkgconfig_DATA = asio.pc
 
 SUBDIRS = include src
 
--- a/configure.ac
+++ b/configure.ac
@@ -8,7 +8,7 @@ AM_PROG_CC_C_O
 AC_PROG_CXX
 AC_LANG(C++)
 AC_PROG_RANLIB
-PKG_INSTALLDIR
+PKG_NOARCH_INSTALLDIR
 
 AC_DEFINE(_REENTRANT, [1], [Define this])