Updated the libpng linux target to use -DCMAKE_POSITION_INDEPENDENT_CODE=1.

This fixes link errors like "relocation R_X86_64_32 against '...' can not be used when making a shared object; recompile with -fPIC".

Signed-off-by: santorac <[email protected]>

package-system/libpng/build_config.json

@@ -56,6 +56,7 @@
                 "cmake_generate_args": [
                     "-DZLIB_ROOT=../../zlib-linux/zlib",
                     "-DCMAKE_POLICY_DEFAULT_CMP0074=NEW",
+                    "-DCMAKE_POSITION_INDEPENDENT_CODE=1",
                     "-DPNG_SHARED=OFF",
                     "-DPNG_TESTS=OFF",
                     "-DPNG_DEBUG=OFF"