fix linker errors due to inline definitions (#1079)

* Rely on "static inline" to also get a copy of the respective function into the library/archive (otherwise we see linker error for code that does not include the header with inline definitions). The "static inline" instead of just "static" avoids warnings about unused functions.
* Fixed copyright banner (make pretty). This change is unrelated to the PR.

src/grid/common/grid_common.h

@@ -43,15 +43,15 @@ static const double fac[] = {
 // \brief Minimum and maximum for integers (missing from the C standard)
 // \author Ole Schuett
 //******************************************************************************
-inline int imin(int x, int y) { return (x < y ? x : y); }
-inline int imax(int x, int y) { return (x > y ? x : y); }
+static inline int imin(int x, int y) { return (x < y ? x : y); }
+static inline int imax(int x, int y) { return (x > y ? x : y); }
 
 //******************************************************************************
 // \brief Equivalent of Fortran's MODULO, which always return a positive number.
 //        https://gcc.gnu.org/onlinedocs/gfortran/MODULO.html
 // \author Ole Schuett
 //******************************************************************************
-inline int modulo(int a, int m) { return ((a % m + m) % m); }
+static inline int modulo(int a, int m) { return ((a % m + m) % m); }
 
 #endif // GRID_COMMON_H
 

src/qs_chargemol.F

@@ -1,6 +1,8 @@
 !--------------------------------------------------------------------------------------------------!
 !   CP2K: A general program to perform molecular dynamics simulations                              !
-!   Copyright (C) 2000 - 2020  CP2K developers group                                               !
+!   Copyright 2000-2020 CP2K developers group <https://cp2k.org>                                   !
+!                                                                                                  !
+!   SPDX-License-Identifier: GPL-2.0-or-later                                                      !
 !--------------------------------------------------------------------------------------------------!
 
 ! **************************************************************************************************