Merge pull request #79 from bavay/master

Adding SPDX license identifiers

tinyexpr.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Zlib
 /*
  * TINYEXPR - Tiny recursive descent parser and evaluation engine in C
  *

tinyexpr.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Zlib
 /*
  * TINYEXPR - Tiny recursive descent parser and evaluation engine in C
  *