build: search for first match between libcoap-3 and libcoap-3-openssl

build: search for first match between libcoap-3 and libcoap-3-openssl

some libcoap installation has libcoap-3.pc pkgconfig file that symlinks to a specific variant, others don't. Therefore searching for the first successful match between libcoap-3 and libcoap-3-openssl.

This allows other libcoap-3 variants to be used when libcoap-3-openssl is not found.

cmake: add flag to skip tests build

Allowing to skip gtests when not necessary

communication/CMakeLists.txt

@@ -6,7 +6,7 @@ set(VERSION_MINOR 1)
 
 find_package(PkgConfig REQUIRED)
 find_package(Threads)
-pkg_check_modules(Coap REQUIRED IMPORTED_TARGET libcoap-3-openssl)
+pkg_search_module(Coap REQUIRED IMPORTED_TARGET libcoap-3 libcoap-3-openssl)
 
 if(CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     add_compile_definitions(DEBUG)