Use relative paths in copygcclib.sh deps files

Strip $PWD/ off the beginning of the path printed by gcc.

Bug: 68719465
Test: m checkbuild
Test: prebuilts/build-tools/linux-x86/bin/ninja -f out/combined-${TARGET_PRODUCT}.ninja -t deps | grep -E '^[[:space:]]*/' | sort | uniq

scripts/copygcclib.sh

@@ -2,6 +2,6 @@
 
 OUT=$1
 shift
-LIBPATH=$($@)
+LIBPATH=$($@ | sed -e "s|^$PWD/||")
 cp -f $LIBPATH $OUT
 echo "$OUT: $LIBPATH" > ${OUT}.d