cmake: avoid unused parameters in cmake tests

unused parameters in cmake tests cause the tests to fail when the
project is configured with `-Werror,-Wunused-parameter`

Change-Id: If3065d008753a7718282dfc6ba0d79d46576cb34
Pick-to: 6.2 6.3
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

cmake/3rdparty/extra-cmake-modules/find-modules/FindEGL.cmake

@@ -123,7 +123,7 @@ list(APPEND CMAKE_REQUIRED_DEFINITIONS "${EGL_DEFINITIONS}")
 check_cxx_source_compiles("
 #include <EGL/egl.h>
 
-int main(int argc, char *argv[]) {
+int main(int, char **) {
     EGLint x = 0; EGLDisplay dpy = 0; EGLContext ctx = 0;
     eglDestroyContext(dpy, ctx);
 }" HAVE_EGL)

cmake/FindGLESv2.cmake

@@ -26,7 +26,7 @@ else()
 #  include <GLES2/gl2.h>
 #endif
 
-int main(int argc, char *argv[]) {
+int main(int, char **) {
     glUniform1f(1, GLfloat(1.0));
     glClear(GL_COLOR_BUFFER_BIT);
 }" HAVE_GLESv2)

cmake/FindWrapRt.cmake

@@ -21,7 +21,7 @@ check_cxx_source_compiles("
 #include <unistd.h>
 #include <time.h>
 
-int main(int argc, char *argv[]) {
+int main(int, char **) {
     timespec ts; clock_gettime(CLOCK_REALTIME, &ts);
 }" HAVE_GETTIME)