Build everything as C++ (#1176)

src/version.cpp

@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: MIT */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "helpers.hpp"
+#include "version.hpp"
+
+// This variable is passed via `-D` from the Makefile, but not from CMake
+// (in which `configure_file()` is used on this file to replace some syntax)
+#ifndef BUILD_VERSION_STRING
+// CMake-specific syntax here
+#define BUILD_VERSION_STRING "@GIT_REV@"
+#endif
+
+char const *get_package_version_string(void)
+{
+	// The following conditional should be simplified by the compiler.
+	if (strlen(BUILD_VERSION_STRING) == 0) {
+		// Fallback if version string can't be obtained from Git
+#ifndef PACKAGE_VERSION_RC
+		return "v" EXPAND_AND_STR(PACKAGE_VERSION_MAJOR)
+			"." EXPAND_AND_STR(PACKAGE_VERSION_MINOR)
+			"." EXPAND_AND_STR(PACKAGE_VERSION_PATCH);
+#else
+		return "v" EXPAND_AND_STR(PACKAGE_VERSION_MAJOR)
+			"." EXPAND_AND_STR(PACKAGE_VERSION_MINOR)
+			"." EXPAND_AND_STR(PACKAGE_VERSION_PATCH)
+			"-rc" EXPAND_AND_STR(PACKAGE_VERSION_RC);
+#endif
+	} else {
+		return BUILD_VERSION_STRING;
+	}
+}