Make the c and ac scripts work with sh and without bin in PATH

bin/c

 #!/bin/sh
 
 set -e
 
 BRANCH=$(git branch | grep \* | cut -d" "  -f 2)
 CLEAN=${CLEAN-clean}
 SAMPLES=100
 
-if [ $BRANCH == $CLEAN ]; then
+if [ "$BRANCH" = "$CLEAN" ]; then
     echo "Comparing $BRANCH to itself."
     exit 1
 fi
 
 if [ ! -f $CLEAN.log ]; then
     git checkout $CLEAN
     ./gyp_skia >/dev/null
     ninja -C out/Release nanobench
     out/Release/nanobench $@ --samples $SAMPLES -v 2> $CLEAN.log
 fi
 
 git checkout $BRANCH
 ./gyp_skia >/dev/null
 ninja -C out/Release nanobench
 out/Release/nanobench $@ --samples $SAMPLES -v 2> $BRANCH.log
 
-compare $CLEAN.log $BRANCH.log
+./bin/compare $CLEAN.log $BRANCH.log