build: Improve cygwin build support

Partially support cygwin environment by adding --no-build to
update_external_sources.sh

Change-Id: I9fa35d6c720dd05a11c307d3da4d09415934899e

3 files changed, 73 insertions, 38 deletions

diff --git a/BUILD.md b/BUILD.md
index da9f3e0c..d88eb9a2 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -194,7 +194,7 @@ Windows 7+ with additional required software packages:
   - Need python3.3 or later to get the Windows py.exe launcher that is used to get python3 rather than python2 if both are installed on Windows
   - 32 bit python works
 - [Git](http://git-scm.com/download/win).
-  - Note: If you use Cygwin, you can normally use Cygwin's "git.exe".  However, in order to use the "update\_external\_sources.bat" script, you must have this version.
+  - Note: If you use Cygwin, you can normally use Cygwin's "git.exe", and "update\_external\_sources.sh --no-build" does support Cygwin's git.  However, in order to use the "update\_external\_sources.bat" script, you must have this version.
   - Tell the installer to allow it to be used for "Developer Prompt" as well as "Git Bash".
   - Tell the installer to treat line endings "as is" (i.e. both DOS and Unix-style line endings).
   - Install each a 32-bit and a 64-bit version, as the 64-bit installer does not install the 32-bit libraries and tools.
@@ -225,6 +225,15 @@ This is described in a `LoaderAndLayerInterface` document in the `loader` folder
 This specification describes both how ICDs and layers should be properly
 packaged, and how developers can point to ICDs and layers within their builds.
 
+### Cygwin
+
+If you are using Cygwin git instead of win32-native git, you can use Cygwin's git to sync external sources:
+```
+./update_external_sources.sh --no-build
+```
+
+Unfortunately, "update\_external\_sources.bat" does not have a --no-sync option. To build the external sources you have to modify "update\_external\_sources.bat" to skip the sync portions of the script.
+
 ## Android Build
 Install the required tools for Linux and Windows covered above, then add the following.
 ### Android Studio
diff --git a/update_external_sources.bat b/update_external_sources.bat
index b6a99113..c0b41a2b 100644
--- a/update_external_sources.bat
+++ b/update_external_sources.bat
@@ -105,7 +105,7 @@ REM // ======== Dependency checking ======== //
       if not defined FOUND (
          echo Dependency check failed:
          echo   cmake.exe not found
-         echo   Get CNake 2.8 for Windows here:  http://www.cmake.org/cmake/resources/software.html
+         echo   Get CMake for Windows here:  http://www.cmake.org/cmake/resources/software.html
          echo   Install and ensure each makes it into your PATH, default is "C:\Program Files (x86)\CMake\bin"
          set errorCode=1
       )
diff --git a/update_external_sources.sh b/update_external_sources.sh
index 78f21f97..30be3d3a 100755
--- a/update_external_sources.sh
+++ b/update_external_sources.sh
@@ -3,13 +3,14 @@
 
 set -e
 
-if [[ $(uname) == "Linux" ]]; then
+if [[ $(uname) == "Linux" || $(uname) =~ "CYGWIN" ]]; then
     CURRENT_DIR="$(dirname "$(readlink -f ${BASH_SOURCE[0]})")"
     CORE_COUNT=$(nproc || echo 4)
 elif [[ $(uname) == "Darwin" ]]; then
     CURRENT_DIR="$(dirname "$(python -c 'import os,sys;print(os.path.realpath(sys.argv[1]))' ${BASH_SOURCE[0]})")"
     CORE_COUNT=$(sysctl -n hw.ncpu || echo 4)
 fi
+echo CURRENT_DIR=$CURRENT_DIR
 echo CORE_COUNT=$CORE_COUNT
 
 REVISION_DIR="$CURRENT_DIR/external_revisions"
@@ -95,57 +96,82 @@ function build_spirv-tools () {
    make -j $CORE_COUNT
 }
 
-# If any options are provided, just compile those tools
-# If no options are provided, build everything
+# If any options are provided, just sync and compile those tools
+# If no options are provided, sync and build everything
 INCLUDE_GLSLANG=false
 INCLUDE_SPIRV_TOOLS=false
-
-if [ "$#" == 0 ]; then
+NO_SYNC=false
+NO_BUILD=false
+USE_IMPLICIT_COMPONENT_LIST=true
+
+# Parse options
+while [[ $# > 0 ]]
+do
+  option="$1"
+
+  case $option in
+      # options to specify build of glslang components
+      -g|--glslang)
+      INCLUDE_GLSLANG=true
+      USE_IMPLICIT_COMPONENT_LIST=false
+      echo "Building glslang ($option)"
+      ;;
+      # options to specify build of spirv-tools components
+      -s|--spirv-tools)
+      INCLUDE_SPIRV_TOOLS=true
+      USE_IMPLICIT_COMPONENT_LIST=false
+      echo "Building spirv-tools ($option)"
+      ;;
+      # option to specify skipping sync from git
+      --no-sync)
+      NO_SYNC=true
+      echo "Skipping sync ($option)"
+      ;;
+      # option to specify skipping build
+      --no-build)
+      NO_BUILD=true
+      echo "Skipping build ($option)"
+      ;;
+      *)
+      echo "Unrecognized option: $option"
+      echo "Try the following:"
+      echo " -g | --glslang      # enable glslang"
+      echo " -s | --spirv-tools  # enable spirv-tools"
+      echo " --no-sync           # skip sync from git"
+      echo " --no-build          # skip build"
+      exit 1
+      ;;
+  esac
+  shift
+done
+
+if [ ${USE_IMPLICIT_COMPONENT_LIST} == "true" ]; then
   echo "Building glslang, spirv-tools"
   INCLUDE_GLSLANG=true
   INCLUDE_SPIRV_TOOLS=true
-else
-  # Parse options
-  while [[ $# > 0 ]]
-  do
-    option="$1"
-
-    case $option in
-        # options to specify build of glslang components
-        -g|--glslang)
-        INCLUDE_GLSLANG=true
-        echo "Building glslang ($option)"
-        ;;
-        # options to specify build of spirv-tools components
-        -s|--spirv-tools)
-        INCLUDE_SPIRV_TOOLS=true
-        echo "Building spirv-tools ($option)"
-        ;;
-        *)
-        echo "Unrecognized option: $option"
-        echo "Try the following:"
-        echo " -g | --glslang      # enable glslang"
-        echo " -s | --spirv-tools  # enable spirv-tools"
-        exit 1
-        ;;
-    esac
-    shift
-  done
 fi
 
 if [ ${INCLUDE_GLSLANG} == "true" ]; then
-  if [ ! -d "${BASEDIR}/glslang" -o ! -d "${BASEDIR}/glslang/.git" -o -d "${BASEDIR}/glslang/.svn" ]; then
-     create_glslang
+  if [ ${NO_SYNC} == "false" ]; then
+    if [ ! -d "${BASEDIR}/glslang" -o ! -d "${BASEDIR}/glslang/.git" -o -d "${BASEDIR}/glslang/.svn" ]; then
+       create_glslang
+    fi
+    update_glslang
+  fi
+  if [ ${NO_BUILD} == "false" ]; then
+    build_glslang
   fi
-  update_glslang
-  build_glslang
 fi
 
 
 if [ ${INCLUDE_SPIRV_TOOLS} == "true" ]; then
+  if [ ${NO_SYNC} == "false" ]; then
     if [ ! -d "${BASEDIR}/spirv-tools" -o ! -d "${BASEDIR}/spirv-tools/.git" ]; then
        create_spirv-tools
     fi
     update_spirv-tools
+  fi
+  if [ ${NO_BUILD} == "false" ]; then
     build_spirv-tools
+  fi
 fi