Merge pull request libgit2#4678 from staticfloat/sf/mbedtls_linkage

Link `mbedTLS` libraries in when `SHA1_BACKEND` == "mbedTLS"

Author: pks-t

.travis.yml

@@ -58,12 +58,12 @@ matrix:
    - compiler: gcc
      env:
          MBEDTLS=1
-         OPTIONS="-DTHREADSAFE=ON -DCMAKE_BUILD_TYPE=Release -DUSE_HTTPS=mbedTLS -DMBEDTLS_ROOT_DIR=../deps/mbedtls"
+         OPTIONS="-DTHREADSAFE=ON -DCMAKE_BUILD_TYPE=Release -DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DMBEDTLS_ROOT_DIR=../deps/mbedtls"
      os: linux
    - compiler: gcc
      env:
          MBEDTLS=1
-         OPTIONS="-DTHREADSAFE=OFF -DBUILD_EXAMPLES=ON -DUSE_HTTPS=mbedTLS -DMBEDTLS_ROOT_DIR=../deps/mbedtls"
+         OPTIONS="-DTHREADSAFE=OFF -DBUILD_EXAMPLES=ON -DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DMBEDTLS_ROOT_DIR=../deps/mbedtls"
      os: linux
  allow_failures:
    - env: COVERITY=1

src/CMakeLists.txt

@@ -284,8 +284,13 @@ ELSEIF(SHA1_BACKEND STREQUAL "CommonCrypto")
 ELSEIF (SHA1_BACKEND STREQUAL "mbedTLS")
 	ADD_FEATURE_INFO(SHA ON "using mbedTLS")
 	SET(GIT_SHA1_MBEDTLS 1)
-	FILE(GLOB SRC_SHA1 src/hash/hash_mbedtls.c)
-	LIST(APPEND LIBGIT2_PC_REQUIRES "mbedtls")
+	FILE(GLOB SRC_SHA1 hash/hash_mbedtls.c)
+	LIST(APPEND LIBGIT2_INCLUDES ${MBEDTLS_INCLUDE_DIR})
+	LIST(APPEND LIBGIT2_LIBS ${MBEDTLS_LIBRARIES})
+	# mbedTLS has no pkgconfig file, hence we can't require it
+	# https://github.com/ARMmbed/mbedtls/issues/228
+	# For now, pass its link flags as our own
+	LIST(APPEND LIBGIT2_PC_LIBS ${MBEDTLS_LIBRARIES})
 ELSE()
 	MESSAGE(FATAL_ERROR "Asked for unknown SHA1 backend ${SHA1_BACKEND}")
 ENDIF()