gen_msvs_*proj.sh: strip SRC_PATH_BARE from obj names

reduces the risk of exceeding msbuild command line length limits

Change-Id: I0e4d807f42c090a709a3dc365a02b929a3071688

build/make/gen_msvs_proj.sh

diff --git a/build/make/gen_msvs_proj.sh b/build/make/gen_msvs_proj.sh
index c6fef0d..660436d 100755
--- a/build/make/gen_msvs_proj.sh
+++ b/build/make/gen_msvs_proj.sh
@@ -67,7 +67,9 @@
             if [ "${f##*.}" == "$pat" ]; then
                 unset file_list[i]
 
-                objf=$(echo ${f%.*}.obj | sed -e 's/^[\./]\+//g' -e 's,[:/ ],_,g')
+                objf=$(echo ${f%.*}.obj \
+                       | sed -e "s,$src_path_bare,," \
+                             -e 's/^[\./]\+//g' -e 's,[:/ ],_,g')
                 open_tag File RelativePath="$f"
 
                 if [ "$pat" == "asm" ] && $asm_use_custom_step; then

build/make/gen_msvs_vcxproj.sh

diff --git a/build/make/gen_msvs_vcxproj.sh b/build/make/gen_msvs_vcxproj.sh
index 60a56c9..4ae511e 100755
--- a/build/make/gen_msvs_vcxproj.sh
+++ b/build/make/gen_msvs_vcxproj.sh
@@ -78,7 +78,9 @@
             if [ "${f##*.}" == "$pat" ]; then
                 unset file_list[i]
 
-                objf=$(echo ${f%.*}.obj | sed -e 's/^[\./]\+//g' -e 's,[:/ ],_,g')
+                objf=$(echo ${f%.*}.obj \
+                       | sed -e "s,$src_path_bare,," \
+                             -e 's/^[\./]\+//g' -e 's,[:/ ],_,g')
 
                 if ([ "$pat" == "asm" ] || [ "$pat" == "s" ]) && $asm_use_custom_step; then
                     # Avoid object file name collisions, i.e. vpx_config.c and