Bundled CVODE contains CMake script with C99 compatibility issue

The C/Fortran linking test always fails with C compilers which do not implement implicit function declarations (a language feature removed in C99; future compilers are likely to disable them by default because they are a programmer hazard). Something like this is needed:

diff -up bionetgen-BioNetGen-2.8.4/bng2/Network3/cvode-2.6.0/config/SundialsFortran.cmake.c99 bionetgen-BioNetGen-2.8.4/bng2/Network3/cvode-2.6.0/config/SundialsFortran.cmake
--- bionetgen-BioNetGen-2.8.4/bng2/Network3/cvode-2.6.0/config/SundialsFortran.cmake.c99    2009-05-10 02:02:59.000000000 +0200
+++ bionetgen-BioNetGen-2.8.4/bng2/Network3/cvode-2.6.0/config/SundialsFortran.cmake    2022-12-11 18:44:28.015918587 +0100
@@ -111,7 +111,7 @@ if(CMAKE_Fortran_COMPILER)
       # Get the current list entry (current scheme)
       list(GET options ${iopt} opt)
       # Generate C source which calls the "mysub" function using the current scheme
-      file(WRITE ${FortranTest_DIR}/ctest1.c "int main(){${opt}();return(0);}\n")
+      file(WRITE ${FortranTest_DIR}/ctest1.c "char ${opt}(void); int main(){${opt}();return(0);}\n")
       # Use TRY_COMPILE to make the "ctest1" executable from the current C source
       # and linking to the previously created "flib" library.
       try_compile(CTEST_OK ${FortranTest_DIR} ${FortranTest_DIR}
@@ -149,7 +149,7 @@ if(CMAKE_Fortran_COMPILER)
     set(iopt 0)
     while(${iopt} LESS ${imax})   
       list(GET options ${iopt} opt)
-      file(WRITE ${FortranTest_DIR}/ctest2.c "int main(){${opt}();return(0);}\n")
+      file(WRITE ${FortranTest_DIR}/ctest2.c "char ${opt}(void); int main(){${opt}();return(0);}\n")
       try_compile(CTEST_OK ${FortranTest_DIR} ${FortranTest_DIR}
         ctest2 OUTPUT_VARIABLE MY_OUTPUT)
       file(REMOVE_RECURSE ${FortranTest_DIR}/CMakeFiles)

Ordinarily I would send a PR, but the sources are contained in a tarball in the repository. I couldn't find any pre-existing patches.

Upstream CVODE has resolved it in pretty much the same way (although they use void ${opt}(void);; the char return type is the autoconf way).

Found as part of:

RuleWorld / bionetgen

Bundled CVODE contains CMake script with C99 compatibility issue #262