From: Jo-Philipp Wich Date: Wed, 11 Jan 2017 03:36:04 +0100 Subject: [PATCH] cmcurl: link librt When cmake is linked against LibreSSL, there might be an indirect dependency on librt on certain systems if LibreSSL's libcrypto uses clock_gettime() from librt: [ 28%] Linking C executable LIBCURL .../lib/libcrypto.a(getentropy_linux.o): In function `getentropy_fallback': getentropy_linux.c:(.text+0x16d): undefined reference to `clock_gettime' getentropy_linux.c:(.text+0x412): undefined reference to `clock_gettime' collect2: error: ld returned 1 exit status make[5]: *** [Utilities/cmcurl/LIBCURL] Error 1 Modify the cmcurl CMakeLists.txt to check for clock_gettime() in librt and unconditionally link the rt library when the symbol is found. Signed-off-by: Jo-Philipp Wich --- --- a/Utilities/cmcurl/CMakeLists.txt +++ b/Utilities/cmcurl/CMakeLists.txt @@ -648,6 +648,14 @@ if(CURL_USE_OPENSSL) endif() set(SSL_ENABLED ON) set(USE_OPENSSL ON) + check_library_exists("rt" clock_gettime "" HAVE_LIBRT) + if(HAVE_LIBRT) + list(APPEND OPENSSL_LIBRARIES rt) + endif() + check_library_exists("pthread" pthread_once "" HAVE_PTHREAD) + if(HAVE_PTHREAD) + list(APPEND OPENSSL_LIBRARIES pthread) + endif() list(APPEND CURL_LIBS ${OPENSSL_LIBRARIES}) include_directories(${OPENSSL_INCLUDE_DIR})