imgproc: move stb_trutype functions into cv namespace

modules/imgproc/src/stb_truetype.cpp

@@ -403,6 +403,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #ifdef STB_TRUETYPE_IMPLEMENTATION
 
+namespace cv {
+
 #ifndef STBTT_MAX_OVERSAMPLE
 #define STBTT_MAX_OVERSAMPLE   8
 #endif
@@ -4428,6 +4430,8 @@ STBTT_DEF int stbtt_SetInstance(stbtt_fontinfo* info, const int* params, int cou
 #pragma GCC diagnostic pop
 #endif
 
+} // namespace cv
+
 #endif // STB_TRUETYPE_IMPLEMENTATION
 
 

modules/imgproc/src/stb_truetype.hpp

@@ -72,7 +72,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #endif
 
 #ifdef __cplusplus
-extern "C" {
+namespace cv {
 #endif
 
 #define STBTT_FOURCC(a, b, c, d) \