Provide missing .pc files for 10.8

10.8 no longer ships four .pc files which were included in previous
versions, though it does still include the libraries which they pointed
to. This commit provides copies of the .pc files for all of these, and
prepends Library/Homebrew/pkgconfig to PKG_CONFIG_PATH on 10.8.

The .pc files in question are: lib curl, lubexslt, libxml-2.0, libxslt

Fixes Homebrew/homebrew#13673.
Fixes Homebrew/homebrew#13627.
Fixes Homebrew/homebrew#13652.
Fixes Homebrew/homebrew#13482.
Closes Homebrew/homebrew#13572.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>

Library/Homebrew/extend/ENV.rb

@@ -9,6 +9,12 @@ module HomebrewEnvExtension
     delete('CLICOLOR_FORCE') # autotools doesn't like this
     remove_cc_etc
 
+    # Mountain Lion no longer ships a few .pcs; make sure we pick up our versions
+    if MacOS.mountain_lion?
+      prepend 'PKG_CONFIG_PATH',
+        HOMEBREW_REPOSITORY/'Library/Homebrew/pkgconfig', ':'
+    end
+
     # make any aclocal stuff installed in Homebrew available
     self['ACLOCAL_PATH'] = "#{HOMEBREW_PREFIX}/share/aclocal" if MacOS::Xcode.provides_autotools?
 

Library/Homebrew/pkgconfig/libcurl.pc

@@ -0,0 +1,39 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 2004 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at http://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
+
+# This should most probably benefit from getting a "Requires:" field added
+# dynamically by configure.
+#
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+supported_protocols="DICT FILE FTP FTPS GOPHER HTTP HTTPS IMAP IMAPS LDAP LDAPS POP3 POP3S RTSP SMTP SMTPS TELNET TFTP"
+supported_features="SSL IPv6 libz AsynchDNS NTLM"
+
+Name: libcurl
+URL: http://curl.haxx.se/
+Description: Library to transfer files with ftp, http, etc.
+Version: 7.21.4
+Libs: -L${libdir} -lcurl 
+Libs.private: -lssl -lcrypto -Wl,-weak-lldap -Wl,-weak-lgssapi_krb5 -lresolv -lssl -lcrypto -lz -lz 
+Cflags: -I${includedir}

Library/Homebrew/pkgconfig/libexslt.pc

@@ -0,0 +1,12 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+
+Name: libexslt
+Version: 0.8.13
+Description: EXSLT Extension library
+Requires: libxml-2.0
+Libs: -L${libdir} -lexslt -lxslt  -lxml2 -lz -lpthread -licucore -lm  
+Cflags: -I${includedir}

Library/Homebrew/pkgconfig/libxml-2.0.pc

@@ -0,0 +1,13 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+modules=1
+
+Name: libXML
+Version: 2.7.3
+Description: libXML library version2.
+Requires:
+Libs: -L${libdir} -lxml2
+Libs.private: -lpthread -lz  -lm 
+Cflags: -I${includedir}/libxml2 

Library/Homebrew/pkgconfig/libxslt.pc

@@ -0,0 +1,12 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+
+Name: libxslt
+Version: 1.1.24
+Description: XSLT library version 2.
+Requires: libxml-2.0
+Libs: -L${libdir} -lxslt  -lxml2 -lz -lpthread -licucore -lm 
+Cflags: -I${includedir}