ColPack detection on MacOS / g++ 10.1 gets confused

[ckirches]

ADOL-C 2.6.3 is confused when detecting ColPack on MacOS, using g++ 10.1 as compiler.

From the ./configure output:

checking ColPack/ColPackHeaders.h presence... yes   
configure: WARNING: ColPack/ColPackHeaders.h: present but cannot be compiled   
configure: WARNING: ColPack/ColPackHeaders.h:     check for missing prerequisite headers?   
configure: WARNING: ColPack/ColPackHeaders.h: see the Autoconf documentation   
configure: WARNING: ColPack/ColPackHeaders.h:     section "Present But Cannot Be Compiled"   
configure: WARNING: ColPack/ColPackHeaders.h: proceeding with the compiler's result   
configure: WARNING:     ## -------------------------------------- ##   
configure: WARNING:     ## Report this to [email protected] ##   
configure: WARNING:     ## -------------------------------------- ##   
checking for ColPack/ColPackHeaders.h... no   

From config.log:

configure:18078: checking ColPack/ColPackHeaders.h usability   
configure:18078: g++ -c -g -O2   -I/opt/local/include -I/Users/ckirches/External/ColPack/Src/build/include conftest.cpp >&5   
In file included from /opt/local/include/gcc10/c++/stdlib.h:36,   
                 from conftest.cpp:68:   
/opt/local/include/gcc10/c++/cstdlib:144:11: error: 'calloc' has not been declared in '::'   
  144 |   using ::calloc;   
      |           ^~~~~~   
/opt/local/include/gcc10/c++/cstdlib:151:11: error: 'malloc' has not been declared in '::'   
  151 |   using ::malloc;   
      |           ^~~~~~   
/opt/local/include/gcc10/c++/cstdlib:164:11: error: 'realloc' has not been declared in '::'   
  164 |   using ::realloc;   
      |           ^~~~~~~
In file included from conftest.cpp:68:   
/opt/local/include/gcc10/c++/stdlib.h:59:12: error: 'calloc' has not been declared in 'std'   
   59 | using std::calloc;   
      |            ^~~~~~   
/opt/local/include/gcc10/c++/stdlib.h:65:12: error: 'malloc' has not been declared in 'std'   
   65 | using std::malloc;   
      |            ^~~~~~   
/opt/local/include/gcc10/c++/stdlib.h:73:12: error: 'realloc' has not been declared in 'std'   
   73 | using std::realloc;   
      |            ^~~~~~~   
configure:18078: $? = 1   
configure: failed program was:   

As per
https://www.gnu.org/software/autoconf/manual/autoconf-2.67/html_node/Present-But-Cannot-Be-Compiled.html
there are dependent headers (#include <cstdlib>) that should be listed in the autoconf script, but are missing. Unfortunately, my autoconf abilities are too limited to provide a fix.

FWIW after a lot of fiddling I managed a build by

• forcing ColPack detecting in configure.ac
• removing #defines for calloc, malloc, and realloc in config.h
• disabling the reverse #defined in common.h inside the ADOLC_NO_MALLOC block