Fix: Add missing math library (-lm) for linker

The CTS build was failing with undefined reference to log10 symbol.
Adding explicit -lm flags to CMAKE_C_FLAGS and CMAKE_EXE_LINKER_FLAGS
ensures the math library is linked properly.

Author: CI Bot

.github/workflows/openvx-conformance.yml

@@ -103,6 +103,8 @@ jobs:
         echo "Running cmake..."
         cmake .. \
           -DCMAKE_BUILD_TYPE=Release \
+          -DCMAKE_C_FLAGS="-lm" \
+          -DCMAKE_EXE_LINKER_FLAGS="-lm" \
           -DOPENVX_INCLUDES="${{ github.workspace }}/include;${{ github.workspace }}/OpenVX-cts/include" \
           -DOPENVX_LIBRARIES="${{ github.workspace }}/target/release/libopenvx_core.so;${{ github.workspace }}/target/release/libopenvx_ffi.so" \
           -DOPENVX_DEFINITIONS="OPENVX_CONFORMANCE_VISION" \