Patch by Andreas Enge to force installation of libraries into lib
independently of the architecture, instead of lib32 or lib64.
On x86_64, the C library path coded in CMAKE_C_IMPLICIT_LINK_DIRECTORIES 
contains a library (jack) installed into lib64, which forces lib64
for avidemux with the original code.

diff -u -r avidemux_2.6.8.orig/cmake/admInstallDir.cmake avidemux_2.6.8/cmake/admInstallDir.cmake
--- avidemux_2.6.8.orig/cmake/admInstallDir.cmake	2014-03-12 07:15:23.000000000 +0100
+++ avidemux_2.6.8/cmake/admInstallDir.cmake	2015-07-26 14:31:10.418459984 +0200
@@ -16,13 +16,7 @@
                 MESSAGE(STATUS "No install dir provided, using /usr/local")
         ENDIF(NOT AVIDEMUX_INSTALL_DIR )
         SET(AVIDEMUX_BIN_DIR ${AVIDEMUX_INSTALL_DIR}/bin)
-        IF(CMAKE_C_IMPLICIT_LINK_DIRECTORIES MATCHES "\\/lib64([; ]|$)")
-                SET(AVIDEMUX_RELATIVE_LIB_DIR lib64)
-        ELSEIF(CMAKE_C_IMPLICIT_LINK_DIRECTORIES MATCHES "\\/lib32([; ]|$)")
-                SET(AVIDEMUX_RELATIVE_LIB_DIR lib32)
-        ELSE(CMAKE_C_IMPLICIT_LINK_DIRECTORIES MATCHES "\\/lib64([; ]|$)")
-                SET(AVIDEMUX_RELATIVE_LIB_DIR lib)
-        ENDIF(CMAKE_C_IMPLICIT_LINK_DIRECTORIES MATCHES "\\/lib64([; ]|$)")
+        SET(AVIDEMUX_RELATIVE_LIB_DIR lib)
         SET(AVIDEMUX_LIB_DIR ${AVIDEMUX_INSTALL_DIR}/${AVIDEMUX_RELATIVE_LIB_DIR})
 ENDIF(WIN32)
 SET(AVIDEMUX_INCLUDE_DIR ${AVIDEMUX_INSTALL_DIR}/include)