GCC version 6 is not enough to build Atomspace, at least 7 or later is required

[Vitaly Bogdanov]

Cogutil macro checks that GCC is 6 or later:

cogutil/cmake/OpenCogGccOptions.cmake

Lines 5 to 9 in d1f3df0

 # Version 6.0 of gcc is required for C++17 support. 
  
 IF (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.0) 
 	MESSAGE(FATAL_ERROR "GCC version must be at least 6.0!") 
 ENDIF (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.0) 

but std::set::merge method which is used in atomspace code:
https://github.com/opencog/atomspace/blob/a633fe2b66cbd9c83cb2d71517a19cc924758703/opencog/atoms/container/JoinLink.cc#L139
was introduced in GCC starting from version 7.

[Nil Geisweiller]

I have personally no problem incrementing the required version of gcc. Note that Debian 9 still uses gcc 6.

[Linas Vepštas]

This implies that Debian 9 won't compile opencog ...

[Linas Vepštas]

Pull req #245 bumps version to 7.0

[Linas Vepštas]

Closing; fixed in #245 I set it to 7.0 but I think its safe to go to 7.5 even, as ubuntu 18.04 LTS has 7.5 in it. Open a new bug if you want something else.