Improve --enable-gcc-warnings for MinGW64

This partially reverts my 2016-05-30 patch.  Apparently MinGW64
still requires pacifications that GCC 7.1.1 x86-64 (Fedora 26)
does not.  Also, pacify tparam.c, which isn’t used on Fedora.
* lib-src/etags.c (process_file_name, TeX_commands):
* src/buffer.c (fix_overlays_before):
* src/data.c (Fmake_variable_buffer_local, cons_to_unsigned)
(cons_to_signed):
* src/editfns.c (Ftranslate_region_internal):
Prefer UNINIT to some stray value, as this simplifies
code-reading later.
* src/eval.c (CACHEABLE): New macro.
(internal_lisp_condition_case): Use it.
* src/tparam.c (tparam1): Use FALLTHROUGH to pacify GCC.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/tparam.c b/src/tparam.c
index 7a4adc2dc94..92fa5b19df7 100644
--- a/src/tparam.c
+++ b/src/tparam.c
@@ -125,6 +125,7 @@ tparam1 (const char *string, char *outstring, int len,
                 goto onedigit;
               if (tem < 100)
                 goto twodigit;
+              FALLTHROUGH;
             case '3':           /* %3 means output in decimal, 3 digits.  */
               if (tem > 999)
                 {
@@ -132,6 +133,7 @@ tparam1 (const char *string, char *outstring, int len,
                   tem %= 1000;
                 }
               *op++ = tem / 100 + '0';
+              FALLTHROUGH;
             case '2':           /* %2 means output in decimal, 2 digits.  */
             twodigit:
               tem %= 100;
@@ -140,10 +142,12 @@ tparam1 (const char *string, char *outstring, int len,
               *op++ = tem % 10 + '0';
               argp++;
               break;
+
             case 'p':           /* %pN means use param N for next subst.  */
               tem = fixed_argp[(*p++) - '1'];
               explicit_param_p = true;
               break;
+
             case 'C':
               /* For c-100: print quotient of value by 96, if nonzero,
                  then do like %+.  */
@@ -152,8 +156,10 @@ tparam1 (const char *string, char *outstring, int len,
                   *op++ = tem / 96;
                   tem %= 96;
                 }
+              FALLTHROUGH;
             case '+':           /* %+x means add character code of char x.  */
               tem += *p++;
+              FALLTHROUGH;
             case '.':           /* %. means output as character.  */
               if (left)
                 {
@@ -173,6 +179,7 @@ tparam1 (const char *string, char *outstring, int len,
                     }
                 }
               *op++ = tem ? tem : 0200;
+              FALLTHROUGH;
             case 'f':           /* %f means discard next arg.  */
               argp++;
               break;