First part of API cleanup: no off_t.

Create and install zipconf.h, which contains definition for
fixed-sized integer types: zip_{,u}int{8,16,32,64}_t.  On systems
where {,u}int{8,16,32,64}_t are defined, they are typedef'ed to
them, on other systems they are typedef'ed to a suitable integer
type.

XXX: Make use of these types internally.

--HG--
branch : HEAD

libzip.pc.in

diff --git a/libzip.pc.in b/libzip.pc.in
index ad1e565..f1301be 100644
--- a/libzip.pc.in
+++ b/libzip.pc.in
@@ -2,6 +2,7 @@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
 includedir=@includedir@
+libincludedir=@libdir@/libzip/include
 
 zipcmp=@prefix@/bin/zipcmp
 
@@ -9,5 +10,5 @@
 Description: library for handling zip archives
 Version: @VERSION@
 Libs: -L${libdir} -lzip @LIBS@
-Cflags: -I${includedir}
+Cflags: -I${includedir} -I${libincludedir}