cmake HAVE_CURL examples

Lewuathe/mlir-hello thirdparty/llvm-project/llvm/cmake/config-ix.cmake :234 

check_symbol_exists(curl_easy_init curl/curl.h HAVE_CURL)

SRB2-Mobile/SRB2-Android src/CMakeLists.txt :184 

target_compile_definitions(SRB2SDL2 PRIVATE -DHAVE_ZLIB -DHAVE_PNG -DHAVE_CURL -D_LARGEFILE64_SOURCE)

root-project/root interpreter/llvm-project/llvm/cmake/config-ix.cmake :198 

check_symbol_exists(curl_easy_init curl/curl.h HAVE_CURL)

d99kris/nmail ext/libetpan/CMakeLists.txt :305 

target_compile_definitions(${LIBNAME} PRIVATE HAVE_CURL=1)