build: Ensure all .pc files are installed

Change-Id: I824e63087021adfda81bd0f867a3fdb5e9efcf7a
diff --git a/Makefile.am b/Makefile.am
index 5f23673..60ec1f8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,7 +5,7 @@
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc libosmogsm.pc \
-		 libosmogb.pc libosmoctrl.pc libosmocoding.pc
+		 libosmogb.pc libosmoctrl.pc libosmocoding.pc libosmosim.pc
 
 @RELMAKE@