added libzmq.pc.in file

configure.in

@@ -372,7 +372,7 @@ AC_CHECK_FUNCS(perror gettimeofday memset socket getifaddrs freeifaddrs)
 
 AC_OUTPUT(Makefile src/Makefile python/Makefile python/setup.py ruby/Makefile \
     java/Makefile perf/Makefile perf/c/Makefile perf/cpp/Makefile \
-    perf/python/Makefile perf/ruby/Makefile perf/java/Makefile)
+    perf/python/Makefile perf/ruby/Makefile perf/java/Makefile src/libzmq.pc)
 
 AC_MSG_RESULT([])
 AC_MSG_RESULT([ ******************************************************** ])

src/Makefile.am

 lib_LTLIBRARIES = libzmq.la
 
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libzmq.pc
 
 if BUILD_CPP
 include_HEADERS = ../cpp/zmq.hpp ../c/zmq.h

src/libzmq.pc.in

+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: libzmq
+Description: 0MQ c++ library
+Version: @VERSION@
+Libs: -L${libdir} -lzmq
+Cflags: -I${includedir}