Shift all compatibility handlinmg from inpcom.c into its own source files

inpcompat.c and inpcompat.h

src/frontend/Makefile.am

@@ -130,6 +130,8 @@ libfte_la_SOURCES = \
     inp.h       \
     inpcom.c    \
     inpcom.h    \
+    inpcompat.c \
+    inpcompat.h \
     inpc_probe.c    \
     interp.c    \
     interp.h    \

src/frontend/inpcom.h

@@ -9,4 +9,8 @@
 struct card *insert_new_line(struct card *card, char *line,
                              int linenum, int linenum_orig);
 char *inp_pathresolve(const char *name);
+
+extern char* inp_remove_ws(char* s);
+extern char* search_plain_identifier(char* str, const char* identifier);
+
 #endif

src/frontend/inpcompat.h

@@ -0,0 +1,20 @@
+/**********
+Copyright 2023 The ngspice team.  All rights reserved.
+License: Three-clause BCD
+Author: 2023 Holger Vogt
+**********/
+
+/*
+  For dealing with compatibility transformations
+
+  PSICE, LTSPICE and others
+*/
+
+extern void print_compat_mode(void);
+extern void set_compat_mode(void);
+extern void pspice_compat_a(struct card* oldcard);
+extern void ltspice_compat_a(struct card* oldcard);
+extern struct card* pspice_compat(struct card* newcard);
+extern struct card* ltspice_compat(struct card* oldcard);
+
+