Run make protoc(.exe) instead of just make, because the latter fails on Cygwin…

Run make protoc(.exe) instead of just make, because the latter fails on Cygwin with mingw gcc; build-protoc.sh works under Cygwin; build-protoc.sh will use the --host parameter consistent with what os-maven-plugin has detected

protoc-artifacts/build-protoc.sh

 #!/bin/bash
 
+# Builds protoc executable into target/protoc.exe
+# To be run from Maven.
+# Usage: build-protoc.sh <OS> <ARCH>
+# <OS> and <ARCH> are ${os.detected.name} and ${os.detected.arch} from os-maven-plugin
+OS=$1
+ARCH=$2
+
+# Under Cygwin, bash doesn't have these in PATH when called from Maven which
+# runs in Windows version of Java.
+export PATH="/bin:/usr/bin:$PATH"
+
+############################################################################
+# Helper functions
+############################################################################
+E_PARAM_ERR=98
+E_ASSERT_FAILED=99
+
+fail()
+{
+  echo "Error: $1"
+  exit $E_ASSERT_FAILED
+}
+
+# Usage: assertEq VAL1 VAL2 $LINENO
+assertEq ()
+{
+  lineno=$3
+  if [ -z "$lineno" ]; then
+    echo "lineno not given"
+    exit $E_PARAM_ERR
+  fi
+
+  if [[ "$1" != "$2" ]]; then
+    echo "Assertion failed:  \"$1\" == \"$2\""
+    echo "File \"$0\", line $lineno"    # Give name of file and line number.
+    exit $E_ASSERT_FAILED
+  fi
+}
+############################################################################
+
+echo "Building protoc, OS=$OS ARCH=$ARCH"
+
 cd $(dirname "$0")
 WORKING_DIR=$(pwd)
+CONFIGURE_ARGS="--disable-shared"
+
+MAKE_TARGET="protoc"
+if [[ "$OS" == windows ]]; then
+  MAKE_TARGET="${MAKE_TARGET}.exe"
+fi
+
+if [[ "$(uname)" == CYGWIN* ]]; then
+  assertEq "$OS" windows $LINENO
+  # Use mingw32 compilers because executables produced by Cygwin compiler
+  # always have dependency on Cygwin DLL.
+  if [[ "$ARCH" == x86_64 ]]; then
+    CONFIGURE_ARGS="$CONFIGURE_ARGS --host=x86_64-w64-mingw32"
+  elif [[ "$ARCH" == x86_32 ]]; then
+    CONFIGURE_ARGS="$CONFIGURE_ARGS --host=i686-pc-mingw32"
+  else
+    fail "Unsupported arch by CYGWIN: $ARCH"
+  fi
+elif [[ "$(uname)" == MINGW32* ]]; then
+  assertEq "$OS" windows $LINENO
+  assertEq "$ARCH" x86_32 $LINENO
+elif [[ "$(uname)" == Linux* ]]; then
+  assertEq "$OS" linux $LINENO
+  if [[ "$ARCH" == x86_64 ]]; then
+    CONFIGURE_ARGS="$CONFIGURE_ARGS --host=x86_64-linux-gnu"
+  elif [[ "$ARCH" == x86_32 ]]; then
+    CONFIGURE_ARGS="$CONFIGURE_ARGS --host=i686-linux-gnu"
+  else
+    fail "Unsupported arch by CYGWIN: $ARCH"
+  fi
+elif [[ "$(uname)" == Darwin* ]]; then
+  assertEq "$OS" osx $LINENO
+else
+  fail "Unsupported system: $(uname)"
+fi
 
 # Override the default value set in configure.ac that has '-g' which produces
 # huge binary.
@@ -11,14 +88,7 @@ export CXXFLAGS="-DNDEBUG"
 # -s to produce stripped binary
 export LDFLAGS="-static-libgcc -static-libstdc++ -s"
 
-# Under Cygwin we use MinGW GCC because the executable produced by Cygwin GCC
-# depends on Cygwin DLL.
-if [[ "$(uname)" == CYGWIN* ]]; then
-  export CC=i686-pc-mingw32-gcc
-  export CXX=i686-pc-mingw32-c++
-  export CXXCPP=i686-pc-mingw32-cpp
-fi
-
-cd "$WORKING_DIR"/.. && ./configure --disable-shared && make clean && make &&
+cd "$WORKING_DIR"/.. && ./configure $CONFIGURE_ARGS &&
+  cd src && make clean && make $MAKE_TARGET &&
   cd "$WORKING_DIR" && mkdir -p target &&
   (cp ../src/protoc target/protoc.exe || cp ../src/protoc.exe target/protoc.exe)

protoc-artifacts/pom.xml

@@ -57,6 +57,8 @@
           <executable>bash</executable>
           <arguments>
             <argument>build-protoc.sh</argument>
+            <argument>${os.detected.name}</argument>
+            <argument>${os.detected.arch}</argument>
           </arguments>
         </configuration>
       </plugin>