cmake: install pkg-config file

Based on patch by Julien Schueller.

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 23b06b3..d1f6b7a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,9 +1,6 @@
 # TODO:
-# 1. pkgconfig file not yet built.
-# 2. installation not tested.
-# 3. Problems generating html pages.
-# 4. create usable libtool .la file
-# 5. runtest not created
+# 1. Problems generating html pages.
+# 2. create usable libtool .la file
 
 CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
 
@@ -125,7 +122,17 @@
 ADD_SUBDIRECTORY(regress)
 ADD_SUBDIRECTORY(examples)
 
-# TODO: pkgconfig file
+# pkgconfig file
+SET(prefix ${CMAKE_INSTALL_PREFIX})
+SET(exec_prefix \${prefix})
+SET(libdir \${exec_prefix}/lib)
+SET(includedir \${prefix}/include)
+SET(LIBS -lz)
+IF(BZIP2_FOUND)
+  SET(LIBS "${LIBS} -lbz2")
+ENDIF()
+CONFIGURE_FILE(libzip.pc.in libzip.pc @ONLY)
+INSTALL(FILES ${CMAKE_CURRENT_BINARY_DIR}/libzip.pc DESTINATION lib/pkgconfig)
 
 # write out config file
 CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/cmake-config.h.in

THANKS

diff --git a/THANKS b/THANKS
index c1a7cec..f741529 100644
--- a/THANKS
+++ b/THANKS
@@ -29,6 +29,7 @@
 Jay Freeman (saurik) <saurik@saurik.com>
 Joel Ebrahimi <joel.ebrahimi@gmail.com>
 Jono Spiro <jono.spiro@gmail.com>
+Julien Schueller <schueller@phimeca.com>
 Keith Jones <keith@keithjjones.com>
 Kohei Yoshida <kohei.yoshida@gmail.com>
 Leith Bade <leith@mapbox.com>