Added RISC-V RVV diagnostics for PNG.

3rdparty/libpng/CMakeLists.txt

@@ -186,7 +186,7 @@ endif()
 if(PNG_TARGET_ARCHITECTURE MATCHES "^(riscv)")
   include(CheckCCompilerFlag)
   set(PNG_RISCV_RVV_POSSIBLE_VALUES on off)
-  set(PNG_RISCV_RVV "off"
+  set(PNG_RISCV_RVV "on"
     CACHE STRING "Enable RISC-V Vector optimizations: on|off; off is default")
   set_property(CACHE PNG_RISCV_RVV
               PROPERTY STRINGS ${PNG_RISCV_RVV_POSSIBLE_VALUES})

CMakeLists.txt

@@ -1557,6 +1557,8 @@ elseif(WITH_PNG OR HAVE_PNG)
     endif()
   elseif(PNG_LOONGARCH_LSX)
     status("      SIMD Support:" "YES (LoongArch LSX)")
+  elseif(PNG_RISCV_RVV)
+    status("      SIMD Support:" "YES (RISC-V RVV)")
   else()
     status("      SIMD Support:" "NO")
   endif()