Sudden mysterious build errors in standard files included via ofMain.h?

I imagine this is something I caused by adding files and code to my project, but I haven’t been able to deduce what might be wrong, and I wonder if anyone here recognizes this symptom. Suddenly when I try to build my project, it reports many pages of basic errors in standard library files, citing them being included from files of mine that I have not edited since the last time the project built and ran just fine.

I did add one .h file that had only C-style commented-out text in it, which had ended with an unclosed comment “/*”, which of course broke the build, but I fixed that and tried building with no text in that file, but after that, the whole project has just been unable to build despite apparently being ok. I backed out recent changes even though they looked ok, but I still keep getting these weird errors in standard files.

The errors start out like this (and none of them really reference the code I wrote):

In file included from /usr/lib/gcc/x86_64-linux-gnu/7/include/stdint.h:9:0,
                 from /home/dronz/OF/libs/openFrameworks/utils/ofConstants.h:2,
                 from /home/dronz/OF/libs/openFrameworks/ofMain.h:6,
                 from /home/dronz/OF/apps/myApps/Champion/src/UIMode.h:19,
                 from /home/dronz/OF/apps/myApps/Champion/src/modeMainMenu.h:3,
                 from /home/dronz/OF/apps/myApps/Champion/src/modeMainMenu.cpp:1:
/usr/include/stdint.h:286:17: error: missing binary operator before token "("
 #if __GLIBC_USE (IEC_60559_BFP_EXT)

I have been building on Linux and things have been building smoothly otherwise. This is the first time I saw anything like this. I expect I must have an extra bracket character somewhere or something, but I wonder if anyone has seen this before and has a clue?

Ok, so I removed the comment-only .h file, and the 100 pages of errors went away.

Is there a reason why a stray never-included .h file in the project’s top src directory, with just comments something like this would cause libraries to explode into error messages?

/*

Features to work on:

[ ] Add challenger description to receive challenge ChoiceEvent.
[ ] Add summary & description texts to modeChoiceEvent.
[ ] Add response buttons to modeChoiceEvent.
[ ] Add effects to response buttons for receive challenge ChoiceEvent.

[*] Add GetName() to Character 
[*] Add a random name generator
[ ] Replace places that show ID with GetName()

[ ] Have combat involving the PC go to UIM_Combat
[ ] Add some sort of combat resolution to UIM_Combat
[ ] Have combat events offer player option to attend & watch
[ ] Add some UI to UImode_Combat

[ ] Add ability to challenge NPCs 

[ ] Have combat lead to an aftermath event of some sort
[ ] Bleeding & tending to wounds
[ ] prizes & reputation

[ ] Add a verbose log file
[ ] Add options to filter events shown - toggle buttons?

*/