build: Fix API version for cairo and don't hardcode it

Cairo has a different API version that was hardcoded. Define it in a new
variable in configure.ac and use it in AssemblyInfo and Makefile.am.

This fixes make distcheck, as the cairo-sharp.dll assembly was not
getting uninstalled from the GAC.

cairo/AssemblyInfo.cs.in

@@ -1,5 +1,5 @@
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
-[assembly:AssemblyVersion("1.10.0.0")]
+[assembly:AssemblyVersion("@CAIRO_API_VERSION@")]
 [assembly:AssemblyDelaySign(false)]

cairo/Makefile.am

@@ -1,5 +1,5 @@
 ASSEMBLY_NAME = cairo-sharp
-ASSEMBLY_NAME_VERSION = $(ASSEMBLY_NAME),Version=$(API_VERSION)
+ASSEMBLY_NAME_VERSION = $(ASSEMBLY_NAME),Version=$(CAIRO_API_VERSION)
 ASSEMBLY = $(ASSEMBLY_NAME).dll
 SNK = $(srcdir)/mono.snk
 
@@ -11,7 +11,6 @@ CLEANFILES = $(ASSEMBLY) $(ASSEMBLY).mdb
 
 sources = \
 	Antialias.cs \
-	AssemblyInfo.cs \
 	Cairo.cs \
 	Content.cs \
 	Context.cs \
@@ -62,7 +61,7 @@ sources = \
 	XlibSurface.cs \
 	#
 
-build_sources = $(addprefix $(srcdir)/, $(sources))
+build_sources = $(addprefix $(srcdir)/, $(sources)) $(builddir)/AssemblyInfo.cs
 
 $(ASSEMBLY): $(build_sources) $(SNK)
 	@rm -f $(ASSEMBLY).mdb

configure.ac

@@ -7,6 +7,8 @@ AM_MAINTAINER_MODE
 
 API_VERSION=3.0.0.0
 AC_SUBST(API_VERSION)
+CAIRO_API_VERSION=1.10.0.0
+AC_SUBST(CAIRO_API_VERSION)
 POLICY_VERSIONS=""
 AC_SUBST(POLICY_VERSIONS)
 
@@ -230,6 +232,7 @@ gio/Makefile
 gio/gio-sharp-3.0.pc
 gio/gio-sharp.dll.config
 gio/glue/Makefile
+cairo/AssemblyInfo.cs
 cairo/Makefile
 pango/Makefile
 pango/pango-sharp.dll.config