aws-sdk-cpp: Fix library and include paths in generated cmake files

AWS's SDK by default tries to prepend its install root to each of the
library paths; this obviously fails with the absolute paths that Nix
gives it. Worse, it computes the installation root by walking up the
filesystem from its cmake file, so even if the AWSSDK_ROOT_DIR is
explicitly set to the root directory, it gets replaced with the path
to the derivation's dev output.

This is all fixed with a patch to the cmake files that generate the
installed configuration.

Once this is fixed, it *still* doesn't work because the export
generator built into cmake insists on adding `$out/include` to the
header search path; when importing this configuration in another
package, cmake will fail because `$out/include` doesn't exist (After
all, it was relocated by a fixup hook). A small postFixupHook will
recreate the directory and make cmake happy.

2 files changed, 82 insertions, 0 deletions

diff --git a/pkgs/development/libraries/aws-sdk-cpp/cmake-dirs.patch b/pkgs/development/libraries/aws-sdk-cpp/cmake-dirs.patch
new file mode 100644
index 000000000000..6e4cad9e73cf
--- /dev/null
+++ b/pkgs/development/libraries/aws-sdk-cpp/cmake-dirs.patch
@@ -0,0 +1,75 @@
+diff --git a/cmake/AWSSDKConfig.cmake b/cmake/AWSSDKConfig.cmake
+index e87252123e..5457bd5910 100644
+--- a/cmake/AWSSDKConfig.cmake
++++ b/cmake/AWSSDKConfig.cmake
+@@ -82,6 +82,7 @@ if (AWSSDK_ROOT_DIR)
+             )
+ else()
+     find_file(AWSSDK_CORE_HEADER_FILE Aws.h
++        "/${AWSSDK_INSTALL_INCLUDEDIR}/aws/core"
+         "/usr/${AWSSDK_INSTALL_INCLUDEDIR}/aws/core"
+         "/usr/local/${AWSSDK_INSTALL_INCLUDEDIR}/aws/core"
+         "C:/Progra~1/AWSSDK/${AWSSDK_INSTALL_INCLUDEDIR}/aws/core"
+@@ -97,14 +98,18 @@ if (NOT AWSSDK_CORE_HEADER_FILE)
+     message(FATAL_ERROR "AWS SDK for C++ is missing, please install it first")
+ endif()
+ 
+-# based on core header file path, inspects the actual AWSSDK_ROOT_DIR
+-get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_CORE_HEADER_FILE}" PATH)
+-get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
+-get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
+-get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
+-
+-if (NOT AWSSDK_ROOT_DIR)
+-    message(FATAL_ERROR "AWSSDK_ROOT_DIR is not set or can't be calculated from the path of core header file")
++if (IS_ABSOLUTE ${AWSSDK_INSTALL_LIBDIR})
++    set(AWSSDK_ROOT_DIR "")
++else()
++    # based on core header file path, inspects the actual AWSSDK_ROOT_DIR
++    get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_CORE_HEADER_FILE}" PATH)
++    get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
++    get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
++    get_filename_component(AWSSDK_ROOT_DIR "${AWSSDK_ROOT_DIR}" PATH)
++
++    if (NOT AWSSDK_ROOT_DIR)
++	message(FATAL_ERROR "AWSSDK_ROOT_DIR is not set or can't be calculated from the path of core header file")
++    endif()
+ endif()
+ 
+ 
+diff --git a/cmake/utilities.cmake b/cmake/utilities.cmake
+index 283a14a138..646aea1da3 100644
+--- a/cmake/utilities.cmake
++++ b/cmake/utilities.cmake
+@@ -43,7 +43,8 @@ macro(setup_install)
+                 EXPORT "${PROJECT_NAME}-targets"
+                 ARCHIVE DESTINATION ${ARCHIVE_DIRECTORY}
+                 LIBRARY DESTINATION ${LIBRARY_DIRECTORY}
+-                RUNTIME DESTINATION ${BINARY_DIRECTORY} )
++                RUNTIME DESTINATION ${BINARY_DIRECTORY}
++                INCLUDES DESTINATION ${INCLUDE_DIRECTORY} )
+ 
+         if (BUILD_SHARED_LIBS)
+             install(
+@@ -57,7 +58,8 @@ macro(setup_install)
+             install (TARGETS ${PROJECT_NAME}
+                      ARCHIVE DESTINATION ${ARCHIVE_DIRECTORY}/${SDK_INSTALL_BINARY_PREFIX}/${PLATFORM_INSTALL_QUALIFIER}/\${CMAKE_INSTALL_CONFIG_NAME}
+                      LIBRARY DESTINATION ${LIBRARY_DIRECTORY}/${SDK_INSTALL_BINARY_PREFIX}/${PLATFORM_INSTALL_QUALIFIER}/\${CMAKE_INSTALL_CONFIG_NAME}
+-                     RUNTIME DESTINATION ${BINARY_DIRECTORY}/${SDK_INSTALL_BINARY_PREFIX}/${PLATFORM_INSTALL_QUALIFIER}/\${CMAKE_INSTALL_CONFIG_NAME})
++                     RUNTIME DESTINATION ${BINARY_DIRECTORY}/${SDK_INSTALL_BINARY_PREFIX}/${PLATFORM_INSTALL_QUALIFIER}/\${CMAKE_INSTALL_CONFIG_NAME}
++                     INCLUDES DESTINATION ${INCLUDE_DIRECTORY}/${SDK_INSTALL_BINARY_PREFIX}/${PLATFORM_INSTALL_QUALIFIER}/\${CMAKE_INSTALL_CONFIG_NAME})
+         endif()
+     endif()
+ endmacro()
+diff --git a/toolchains/pkg-config.pc.in b/toolchains/pkg-config.pc.in
+index 9b519d2772..a61069225c 100644
+--- a/toolchains/pkg-config.pc.in
++++ b/toolchains/pkg-config.pc.in
+@@ -1,5 +1,5 @@
+-includedir=@CMAKE_INSTALL_PREFIX@/@INCLUDE_DIRECTORY@
+-libdir=@CMAKE_INSTALL_PREFIX@/@LIBRARY_DIRECTORY@
++includedir=@INCLUDE_DIRECTORY@
++libdir=@LIBRARY_DIRECTORY@
+ 
+ Name: @PROJECT_NAME@
+ Description: @PROJECT_DESCRIPTION@
diff --git a/pkgs/development/libraries/aws-sdk-cpp/default.nix b/pkgs/development/libraries/aws-sdk-cpp/default.nix
index f6878cd9396e..94827743bf3d 100644
--- a/pkgs/development/libraries/aws-sdk-cpp/default.nix
+++ b/pkgs/development/libraries/aws-sdk-cpp/default.nix
@@ -50,6 +50,12 @@ stdenv.mkDerivation rec {
       rm aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp
     '';
 
+  postFixupHooks = [
+    # This bodge is necessary so that the file that the generated -config.cmake file
+    # points to an existing directory.
+    ''mkdir -p $out/include''
+  ];
+
   __darwinAllowLocalNetworking = true;
 
   patches = [
@@ -57,6 +63,7 @@ stdenv.mkDerivation rec {
       url = "https://github.com/aws/aws-sdk-cpp/commit/42991ab549087c81cb630e5d3d2413e8a9cf8a97.patch";
       sha256 = "0myq5cm3lvl5r56hg0sc0zyn1clbkd9ys0wr95ghw6bhwpvfv8gr";
     })
+    ./cmake-dirs.patch
   ];
 
   meta = with lib; {