depot_tools: Simplify MinGW check.

Check `if [[ $(uname -s) = MINGW* ]]` instead of using
grepping and an additional variable.

Change-Id: I6f2cfbb6743357125e6672b77667ee5e36d3d81e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2127674
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>

fetch

@@ -9,16 +9,13 @@ base_dir=$(dirname "$0")
 # standalone, but allow other PATH manipulations to take priority.
 PATH=$PATH:$base_dir
 
-# MINGW will equal 0 if we're running on Windows under MinGW.
-MINGW=$(uname -s | grep MINGW > /dev/null; echo $?)
-
 if [[ $GCLIENT_PY3 == 1 ]]; then
   # Explicitly run on Python 3
   PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/fetch.py" "$@"
 elif [[ $GCLIENT_PY3 == 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/fetch.py" "$@"
-elif [[ $MINGW = 0 ]]; then
+elif [[ $(uname -s) = MINGW* || $(uname -s) = CYGWIN* ]]; then
   # Run on Python 2 on Windows for now, allows default to be flipped.
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/fetch.py" "$@"
 else

gclient

@@ -26,16 +26,13 @@ fi
 # standalone, but allow other PATH manipulations to take priority.
 PATH=$PATH:$base_dir
 
-# MINGW will equal 0 if we're running on Windows under MinGW.
-MINGW=$(uname -s | grep MINGW > /dev/null; echo $?)
-
 if [[ $GCLIENT_PY3 == 1 ]]; then
   # Explicitly run on Python 3
   PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/gclient.py" "$@"
 elif [[ $GCLIENT_PY3 == 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/gclient.py" "$@"
-elif [[ $MINGW = 0 ]]; then
+elif [[ $(uname -s) = MINGW* || $(uname -s) = CYGWIN* ]]; then
   # Run on Python 2 on Windows for now, allows default to be flipped.
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/gclient.py" "$@"
 else

python_runner.sh

@@ -48,16 +48,13 @@ SCRIPT="${SCRIPT-${BASENAME//-/_}.py}"
 # standalone, but allow other PATH manipulations to take priority.
 PATH=$PATH:$DEPOT_TOOLS
 
-# MINGW will equal 0 if we're running on Windows under MinGW.
-MINGW=$(uname -s | grep MINGW > /dev/null; echo $?)
-
 if [[ $GCLIENT_PY3 = 1 ]]; then
   # Explicitly run on Python 3
   vpython3 "$DEPOT_TOOLS/$SCRIPT" "$@"
 elif [[ $GCLIENT_PY3 = 0 ]]; then
   # Explicitly run on Python 2
   vpython "$DEPOT_TOOLS/$SCRIPT" "$@"
-elif [[ $MINGW = 0 ]]; then
+elif [[ $(uname -s) = MINGW* || $(uname -s) = CYGWIN* ]]; then
   # Run on Python 2 on Windows for now, allows default to be flipped.
   vpython "$DEPOT_TOOLS/$SCRIPT" "$@"
 else

roll-dep

@@ -9,16 +9,13 @@ base_dir=$(dirname "$0")
 # standalone, but allow other PATH manipulations to take priority.
 PATH=$PATH:$base_dir
 
-# MINGW will equal 0 if we're running on Windows under MinGW.
-MINGW=$(uname -s | grep MINGW > /dev/null; echo $?)
-
 if [[ $GCLIENT_PY3 = 1 ]]; then
   # Explicitly run on Python 3
   PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/roll_dep.py" "$@"
 elif [[ $GCLIENT_PY3 = 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/roll_dep.py" "$@"
-elif [[ $MINGW = 0 ]]; then
+elif [[ $(uname -s) = MINGW* || $(uname -s) = CYGWIN* ]]; then
   # Run on Python 2 on Windows for now, allows default to be flipped.
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/roll_dep.py" "$@"
 else

vpython3

@@ -39,12 +39,9 @@ base_dir=$(dirname "$0")
 source "$base_dir/cipd_bin_setup.sh"
 cipd_bin_setup &> /dev/null
 
-# MINGW will equal 0 if we're running on Windows under MinGW.
-MINGW=$(uname -s | grep MINGW > /dev/null; echo $?)
-
 # If Python bootstrapping is not disabled, make sure Python has been
 # bootstrapped and add it to the front of PATH.
-if [[ $MINGW = 0 ]]; then
+if [[ $(uname -s) = MINGW* || $(uname -s) = CYGWIN* ]]; then
   cmd.exe //c $0.bat "$@"
 elif [[ $DEPOT_TOOLS_BOOTSTRAP_PYTHON3 != 0 ]]; then
   if [[ ! -e "$base_dir/python3_bin_reldir.txt" ]]; then