fuzz: try and ensure fuzzer tests run against the right python-config

Also only under python 3.

Differential Revision: https://phab.mercurial-scm.org/D9752

tests/test-fuzz-targets.t

@@ -1,64 +1,74
-#require test-repo
+#require test-repo py3
 
   $ cd $TESTDIR/../contrib/fuzz
   $ OUT=$TESTTMP ; export OUT
 
 which(1) could exit nonzero, but that's fine because we'll still end
 up without a valid executable, so we don't need to check $? here.
 
   $ if which gmake >/dev/null 2>&1; then
   >     MAKE=gmake
   > else
   >     MAKE=make
   > fi
 
   $ havefuzz() {
   >     cat > $TESTTMP/dummy.cc <<EOF
   > #include <stdlib.h>
   > #include <stdint.h>
   > int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { return 0; }
   > int main(int argc, char **argv) {
   >     const char data[] = "asdf";
   >     return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);
   > }
   > EOF
   >     $CXX $TESTTMP/dummy.cc -o $TESTTMP/dummy \
   >        -fsanitize=fuzzer-no-link,address || return 1
   > }
 
+Try to find a python3-config that's next to our sys.executable. If
+that doesn't work, fall back to looking for a global python3-config
+and hope that works out for the best.
+  $ PYBIN=`$PYTHON -c 'import sys, os; print(os.path.dirname(sys.executable))'`
+  $ if [ -x "$PYBIN/python3-config" ] ; then
+  >   PYTHON_CONFIG="$PYBIN/python3-config"
+  > else
+  >   PYTHON_CONFIG="`which python3-config`"
+  > fi
+
 #if clang-libfuzzer
   $ CXX=clang++ havefuzz || exit 80
-  $ $MAKE -s clean all PYTHON_CONFIG=`which python-config`
+  $ $MAKE -s clean all PYTHON_CONFIG="$PYTHON_CONFIG"
 #endif
 #if no-clang-libfuzzer clang-6.0
   $ CXX=clang++-6.0 havefuzz || exit 80
-  $ $MAKE -s clean all CC=clang-6.0 CXX=clang++-6.0 PYTHON_CONFIG=`which python-config`
+  $ $MAKE -s clean all CC=clang-6.0 CXX=clang++-6.0 PYTHON_CONFIG="$PYTHON_CONFIG"
 #endif
 #if no-clang-libfuzzer no-clang-6.0
   $ exit 80
 #endif
 
   $ cd $TESTTMP
 
 Run each fuzzer using dummy.cc as a fake input, to make sure it runs
 at all. In the future we should instead unpack the corpus for each
 fuzzer and use that instead.
 
   $ for fuzzer in `ls *_fuzzer | sort` ; do
   >   echo run $fuzzer...
   >   ./$fuzzer dummy.cc > /dev/null 2>&1 
   > done
   run bdiff_fuzzer...
   run dirs_fuzzer...
   run dirstate_fuzzer...
   run fm1readmarkers_fuzzer...
   run fncache_fuzzer...
   run jsonescapeu8fast_fuzzer...
   run manifest_fuzzer...
   run mpatch_fuzzer...
   run revlog_fuzzer...
   run xdiff_fuzzer...
 
 Clean up.
   $ cd $TESTDIR/../contrib/fuzz
   $ $MAKE -s clean