Add checks for C++11 with informative error.

This adds a check_cxx11.cpp source that is checked for compile with the
chosen toolset before actually building. This include an appropriate
user error. To see such errors, we also nolonger output to
bootstrap.log. Instead the bootstrap outputs to cerr and sets the
error code.

bootstrap.bat

@@ -10,12 +10,12 @@ REM (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.t
 :b2_build
 ECHO Building the B2 engine..
 pushd src\engine
-call .\build.bat %* > ..\..\bootstrap.log
+call .\build.bat %*
 @ECHO OFF
 popd
 if exist ".\src\engine\b2.exe" (
-   copy .\src\engine\b2.exe . > nul
-   goto :b2_built)
+    copy .\src\engine\b2.exe . > nul
+    goto :b2_built)
 goto :b2_failure
 
 
@@ -31,7 +31,6 @@ goto :end
 :b2_failure
 ECHO.
 ECHO Failed to build the B2 engine.
-ECHO Please consult bootstrap.log for further diagnostics.
 ECHO.
 goto :end
 

bootstrap.sh

@@ -10,11 +10,10 @@
 # Build b2
 echo "Building the B2 engine.."
 pwd=`pwd`
-(cd "./src/engine" && ./build.sh) > bootstrap.log 2>&1
+( cd "./src/engine" && ./build.sh )
 if [ $? -ne 0 ]; then
     echo
-    echo "Failed to build the B2 engine."
-    echo "Please consult bootstrap.log for further diagnostics."
+    echo "Failed to build the B2 engine." 1>&2
     exit 1
 fi
 cd "$pwd"

src/engine/build.sh

@@ -13,7 +13,7 @@ B2_OS=
 # if there was an error.
 echo_run ()
 {
-    echo "$@"
+    echo "> $@"
     $@
     r=$?
     if test $r -ne 0 ; then
@@ -46,7 +46,7 @@ Similarly, the cross-cxx toolset is available for cross-compiling by using the
 BUILD_CXX, BUILD_CXXFLAGS, and BUILD_LDFLAGS environment variables to compile
 binaries that will be executed on the build system. This allows CXX etc. to be
 set for cross-compilers to be propagated to subprocesses.
-"
+" 1>&2
     exit 1
 }
 
@@ -68,50 +68,86 @@ test_uname ()
     fi
 }
 
+# Check that the given command runs.
+test_exec ()
+{
+    "$*" 1>/dev/null 2>/dev/null
+}
+
+# Check that the compiler can do C++11.
+test_cxx11 ()
+{
+    if ! test $NO_CXX11_CHECK ; then
+        case $1 in
+            gcc) ( ${CXX:=g++} -x c++ -std=c++11 check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            intel-darwin) ( ${CXX:=icc} -xc++ check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            intel-linux) ( ${CXX:=icc} -xc++ check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            vacpp) ( ${CXX:=xlC_r} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            xlcpp) ( ${CXX:=xlC_r} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            como) ( ${CXX:=como} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            kcc) ( ${CXX:=KCC} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            kylix) ( ${CXX:=bc++} -tC -q check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            mipspro) ( ${CXX:=CC} -FE:template_in_elf_section -ptused check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            pathscale) ( ${CXX:=pathCC} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            pgi) ( ${CXX:=pgc++} -std=c++11 check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            sun*) ( ${CXX:=CC} -std=c++11 check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            clang*) ( ${CXX:=clang++} -x c++ -std=c++11 check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            tru64cxx) ( ${CXX:=cc} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            acc) ( ${CXX:=aCC} -AA check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            qcc) ( ${CXX:=QCC} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            cxx) ( ${CXX:=cxx} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            cross-cxx) ( ${CXX:=cxx} check_cxx11.cpp && rm -f a.out ) 1>/dev/null 2>/dev/null ;;
+            *) test "0" = "1" ;;
+        esac
+    else
+        test $NO_CXX11_CHECK
+    fi
+}
+
 # Try and guess the toolset to bootstrap the build with...
 guess_toolset ()
 {
-    if test_uname Darwin ; then B2_TOOLSET=clang
-    elif test_uname IRIX ; then B2_TOOLSET=mipspro
-    elif test_uname IRIX64 ; then B2_TOOLSET=mipspro
-    elif test_uname OSF1 ; then B2_TOOLSET=tru64cxx
-    elif test_uname QNX && test_path QCC ; then B2_TOOLSET=qcc
-    elif test_uname Linux && test_path xlC_r; then
+    if test_uname Darwin && test_cxx11 clang ; then B2_TOOLSET=clang
+    elif test_uname IRIX && test_cxx11 mipspro ; then B2_TOOLSET=mipspro
+    elif test_uname IRIX64 && test_cxx11 mipspro ; then B2_TOOLSET=mipspro
+    elif test_uname OSF1 && test_cxx11 tru64cxx ; then B2_TOOLSET=tru64cxx
+    elif test_uname QNX && test_path QCC && test_cxx11 qcc ; then B2_TOOLSET=qcc
+    elif test_uname Linux && test_path xlC_r ; then
        if /usr/bin/lscpu | grep Byte | grep Little > /dev/null 2>&1 ; then
           # Little endian linux
           B2_TOOLSET=xlcpp
        else
           #Big endian linux
           B2_TOOLSET=vacpp
        fi
-    elif test_uname AIX && test_path xlC_r; then B2_TOOLSET=vacpp
-    elif test_uname FreeBSD && test_path freebsd-version && test_path clang++; then B2_TOOLSET=clang
-    elif test_path g++ ; then B2_TOOLSET=gcc
-    elif test_path clang++ ; then B2_TOOLSET=clang
-    elif test_path icc ; then B2_TOOLSET=intel-linux
-    elif test -r /opt/intel/cc/9.0/bin/iccvars.sh ; then
+    elif test_uname AIX && test_path xlC_r && test_cxx11 vacpp ; then B2_TOOLSET=vacpp
+    elif test_uname FreeBSD && test_path freebsd-version && test_path clang++ && test_cxx11 clang ; then B2_TOOLSET=clang
+    elif test_path g++ && test_cxx11 gcc ; then B2_TOOLSET=gcc
+    elif test_path clang++ && test_cxx11 clang ; then B2_TOOLSET=clang
+    elif test_path icc && test_cxx11 intel-linux ; then B2_TOOLSET=intel-linux
+    elif test -r /opt/intel/cc/9.0/bin/iccvars.sh && test_cxx11 intel-linux ; then
         B2_TOOLSET=intel-linux
         B2_TOOLSET_ROOT=/opt/intel/cc/9.0
-    elif test -r /opt/intel_cc_80/bin/iccvars.sh ; then
+    elif test -r /opt/intel_cc_80/bin/iccvars.sh && test_cxx11 intel-linux ; then
         B2_TOOLSET=intel-linux
         B2_TOOLSET_ROOT=/opt/intel_cc_80
-    elif test -r /opt/intel/compiler70/ia32/bin/iccvars.sh ; then
+    elif test -r /opt/intel/compiler70/ia32/bin/iccvars.sh && test_cxx11 intel-linux ; then
         B2_TOOLSET=intel-linux
         B2_TOOLSET_ROOT=/opt/intel/compiler70/ia32/
-    elif test -r /opt/intel/compiler60/ia32/bin/iccvars.sh ; then
+    elif test -r /opt/intel/compiler60/ia32/bin/iccvars.sh && test_cxx11 intel-linux ; then
         B2_TOOLSET=intel-linux
         B2_TOOLSET_ROOT=/opt/intel/compiler60/ia32/
-    elif test -r /opt/intel/compiler50/ia32/bin/iccvars.sh ; then
+    elif test -r /opt/intel/compiler50/ia32/bin/iccvars.sh && test_cxx11 intel-linux ; then
         B2_TOOLSET=intel-linux
         B2_TOOLSET_ROOT=/opt/intel/compiler50/ia32/
-    elif test_path pgc++ ; then B2_TOOLSET=pgi
-    elif test_path pathCC ; then B2_TOOLSET=pathscale
-    elif test_path como ; then B2_TOOLSET=como
-    elif test_path KCC ; then B2_TOOLSET=kcc
-    elif test_path bc++ ; then B2_TOOLSET=kylix
-    elif test_path aCC ; then B2_TOOLSET=acc
+    elif test_path pgc++ && test_cxx11 pgi ; then B2_TOOLSET=pgi
+    elif test_path pathCC && test_cxx11 pathscale ; then B2_TOOLSET=pathscale
+    elif test_path como && test_cxx11 como ; then B2_TOOLSET=como
+    elif test_path KCC && test_cxx11 kcc ; then B2_TOOLSET=kcc
+    elif test_path bc++ && test_cxx11 kylix ; then B2_TOOLSET=kylix
+    elif test_path aCC && test_cxx11 acc ; then B2_TOOLSET=acc
     elif test_uname HP-UX ; then B2_TOOLSET=acc
-    elif test -r /opt/SUNWspro/bin/cc ; then
+    elif test -r /opt/SUNWspro/bin/cc && test_cxx11 sunpro ; then
         B2_TOOLSET=sunpro
         B2_TOOLSET_ROOT=/opt/SUNWspro/
     # Test for some common compile command as the default fallback.
@@ -147,19 +183,28 @@ check_debug_build ()
 # is the name of the toolset to force building
 # with.
 case "$1" in
-    --guess-toolset) guess_toolset ; echo "$B2_TOOLSET" ; exit 1 ;;
+    --guess-toolset) NO_CXX11_CHECK=1 ; guess_toolset ; echo "$B2_TOOLSET" ; exit 1 ;;
     -*) guess_toolset ;;
     ?*) B2_TOOLSET=$1 ; shift ;;
     *) guess_toolset ;;
 esac
+
+# We need a C++11 compiler. Check here and given some feedback about it.
+if ! test_cxx11 $B2_TOOLSET ; then
+    error_exit "
+A C++11 capable compiler is required for building the B2 engine.
+Toolset '$B2_TOOLSET' does not appear to support C++11.
+"
+fi
+
 case $B2_TOOLSET in
 
     gcc)
         CXX=${CXX:=g++}
         CXX_VERSION_OPT=${CXX_VERSION_OPT:=--version}
         # Check whether it's MinGW GCC, which has Windows headers and none of POSIX ones.
         machine=$(${CXX} -dumpmachine 2>/dev/null)
-        if [ $? -ne 0 ]; then
+        if test $? -ne 0 ; then
             echo "B2_TOOLSET is gcc, but the 'gcc' command cannot be executed."
             echo "Make sure 'gcc' is in PATH, or use a different toolset."
             exit 1
@@ -321,7 +366,7 @@ case $B2_TOOLSET in
     clang*)
         CXX=${CXX:=clang++}
         CXX_VERSION_OPT=${CXX_VERSION_OPT:=--version}
-        B2_CXX="${CXX} -x c++ -O3 -std=c++11"
+        B2_CXX="${CXX} -x c++ -std=c++11"
         B2_TOOLSET=clang
         B2_CXXFLAGS_RELEASE="-O3 -s"
         B2_CXXFLAGS_DEBUG="-O0 -fno-inline -g"
@@ -368,14 +413,18 @@ case $B2_TOOLSET in
     ;;
 esac
 
-echo "###"
-echo "###"
-echo "### Using '$B2_TOOLSET' toolset."
-echo "###"
-echo "###"
+echo "
+###
+###
+### Using '$B2_TOOLSET' toolset.
+###
+###
+"
 echo_run ${CXX} ${CXX_VERSION_OPT}
-echo "###"
-echo "###"
+echo "
+###
+###
+"
 B2_SOURCES="\
  builtins.cpp \
  class.cpp \

src/engine/check_cxx11.cpp

@@ -0,0 +1,21 @@
+/*  Copyright 2020 Rene Rivera
+ *  Distributed under the Boost Software License, Version 1.0.
+ *  (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+/*
+This program is a compile test for support of C++11. If it compiles
+successfully some key parts of C++11 the B2 engine requires are
+available. This is used by the build script to guess and check the
+compiler to build the engine with.
+*/
+
+// Some headers we depend on..
+#include <thread>
+
+
+int main()
+{
+    // Check for basic thread calls.
+    { auto _ = std::thread::hardware_concurrency(); }
+}