Don't try to access /usr/local on Travis CI

.travis.yml

@@ -12,9 +12,9 @@ compiler:
 
 before_script:
  - ./autogen.sh
- - env CC=tcc CFLAGS='-w' ./configure --disable-dependency-tracking --disable-shared || cat config.log
+ - env CC=tcc CFLAGS='-w' ./configure --prefix=/tmp --disable-dependency-tracking --disable-shared || cat config.log
  - make -j $(nproc) && make check && make install
- - ./test/constcheck.sh
+ - env CC=tcc CPPFLAGS='-I/tmp/include' LDFLAGS='-L/tmp/lib' LD_LIBRARY_PATH='/tmp/lib' ./test/constcheck.sh
  - make distclean
 
 script:

test/constcheck.sh

@@ -13,7 +13,7 @@ for macro in $(egrep -r '#define crypto_.*BYTES(_[A-Z]+)? ' src/libsodium/includ
 done
 echo "return 0; }" >> "$CT"
 
-cc "$CT" -lsodium || exit 1
+${CC:-cc} "$CT" $CPPFLAGS $CFLAGS $LDFLAGS -lsodium || exit 1
 ./a.out || exit 1
 rm -f a.out "$CT"