e12c524 Merge branch 'fun_with_flags' into 'master'

BUGS

@@ -18,6 +18,11 @@ General:
 
 Known (recent) bugs:
 
+* WHIZARD 3.0.0 and earlier might not compile together with HepMC3/ROOT
+  when using a genuine C++17 standard compiler like gcc/g++ 11 and newer.
+  This came from backwards compatibility with gcc/g++ 5 as a default
+  C++98 compiler. Fixed in v3.0.1.
+
 * WHIZARD 2.8.5/3.0.0beta and earlier do not support reading LCIO events
   with LCIO versions 2.15 and newer due to a bug in the LCIO interface.
 

ChangeLog

@@ -4,6 +4,9 @@ Use svn log to see detailed changes.
 
 	Version 3.0.0+
 
+2021-07-05
+	Bug fix for C++17 default compilers w/ HepMC3/ROOT interface
+
 2021-07-02
 	Improvement for POWHEG matching:
 	- implement massless recoil case

m4/hepmc.m4

@@ -79,7 +79,7 @@ if test "$enable_hepmc" = "yes"; then
       AC_MSG_CHECKING([the HepMC3 version])
       save_CXXFLAGS="$CXXFLAGS"
       save_LIBS="$LIBS"
-      CXXFLAGS="${CXXFLAGS} --std=c++11 `${hepmcconfig} --cxxflags`"
+      CXXFLAGS="${CXXFLAGS} `${hepmcconfig} --cxxflags`"
       LIBS="${LIBS} -Wl,-rpath,`${hepmcconfig} --libdir` `${hepmcconfig} --libs`"
       AC_LANG([C++])
       AC_LINK_IFELSE([dnl
@@ -165,7 +165,7 @@ else
    save_CXXFLAGS="$CXXFLAGS"
    save_LIBS="$LIBS"
 
-   CXXFLAGS="${CXXFLAGS} --std=c++11 `${hepmcconfig} --cxxflags`"
+   CXXFLAGS="${CXXFLAGS} `${hepmcconfig} --cxxflags`"
    LIBS="${LIBS} `${hepmcconfig} --libs`"
 
    AC_MSG_CHECKING([if HepMC3 is built with ROOT interface])
@@ -193,7 +193,7 @@ using namespace HepMC3; GenEvent evt(Units::GEV,Units::MM);
 
    AC_MSG_CHECKING([for HepMC3])
    if test "${hepmcok}" = "yes"; then
-      HEPMC_INCLUDES="--std=c++11 `${hepmcconfig} --cxxflags` $HEPMCROOTINCL"
+      HEPMC_INCLUDES="`${hepmcconfig} --cxxflags` $HEPMCROOTINCL"
       LDFLAGS_HEPMC="-Wl,-rpath,`${hepmcconfig} --libdir` `${hepmcconfig} --libs` $HEPMCROOTLIBS"
       AC_MSG_RESULT([yes])
       $1

m4/lcio.m4

@@ -16,9 +16,9 @@ AC_ARG_ENABLE([lcio],
 
 # First test for LCIO, then for LCIO_DIR; LCIO takes precedence.
 if test -n "$LCIO"; then
-  wo_lcio_includes="--std=c++11 -I$LCIO/include"
+  wo_lcio_includes="-I$LCIO/include"
 elif test -n "$LCIO_DIR"; then
-  wo_lcio_includes="--std=c++11 -I$LCIO_DIR/include"
+  wo_lcio_includes="-I$LCIO_DIR/include"
 fi
 
 if test "$enable_lcio" = "yes"; then