Various fixes for building with GCC 10.

Taken from Debian:
https://sources.debian.org/patches/jfsutils/1.1.15-5/gcc10_fix-1.patch/

--- jfsutils-1.1.15.old/fscklog/display.c	2005-11-22 21:43:54.000000000 +0100
+++ jfsutils-1.1.15.new/fscklog/display.c	2020-05-21 18:15:13.410617620 +0200
@@ -54,7 +54,7 @@
  * output: fsck extracted service log I/O buffer
  *
  */
-char xchklog_buffer[XCHKLOG_BUFSIZE];
+static char xchklog_buffer[XCHKLOG_BUFSIZE];
 
 /* + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
  *
diff -ur --exclude '*.o' --exclude '*.a' jfsutils-1.1.15.old/libfs/logredo.c jfsutils-1.1.15.new/libfs/logredo.c
--- jfsutils-1.1.15.old/libfs/logredo.c	2005-11-22 21:43:55.000000000 +0100
+++ jfsutils-1.1.15.new/libfs/logredo.c	2020-05-21 18:19:44.927703271 +0200
@@ -87,9 +87,9 @@
  *    S T U F F    F O R    T H E    L O G
  *
  */
-struct logsuper logsup;		/* log super block */
-int32_t numdoblk;		/* number of do blocks used     */
-int32_t numnodofile;		/* number of nodo file blocks used  */
+static struct logsuper logsup;		/* log super block */
+static int32_t numdoblk;		/* number of do blocks used     */
+static int32_t numnodofile;		/* number of nodo file blocks used  */
 int32_t numExtDtPg = 0;		/* number of extended dtpage blocks used  */
 
 /*
@@ -129,7 +129,7 @@
  */
 
 /* buffer header table */
-struct bufhdr {
+static struct bufhdr {
 	int16_t next;		/* 2: next on free/lru list */
 	int16_t prev;		/* 2: previous on free/lru list */
 	int16_t hnext;		/* 2: next on hash chain */
@@ -142,7 +142,7 @@
 } bufhdr[NBUFPOOL];		/* (24) */
 
 /* buffer table */
-struct bufpool {
+static struct bufpool {
 	char bytes[PSIZE];
 } buffer[NBUFPOOL - 1];
 
@@ -151,15 +151,16 @@
  *
  * log has its own 4 page buffer pool.
  */
-uint8_t afterdata[LOGPSIZE * 2];	/* buffer to read in redopage data */
+static uint8_t afterdata[LOGPSIZE * 2];	/* buffer to read in redopage data */
 
 /*
  * Miscellaneous
  */
-caddr_t prog;			/* Program name */
-int32_t mntcnt, bufsize;
-char *mntinfo;
-int32_t retcode;		/* return code from logredo    */
+static caddr_t prog;			/* Program name */
+extern int32_t mntcnt;
+static int32_t bufsize;
+static char *mntinfo;
+static int32_t retcode;		/* return code from logredo    */
 int end_of_transaction = 0;
 
 /*
/packages/xiph.scm?id=c9fd3d1b84086b3f0e95e2473fb40248d202bc53'>xiph.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/xiph.scm?id=c9fd3d1b84086b3f0e95e2473fb40248d202bc53&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-14 17:15:08 -0400'>2023-04-14</span></td><td><a href='/guix/commit/gnu/packages/xiph.scm?id=3bacd3c76a58ebe70f98be654f09cbd4166093ab'>Merge branch 'master' into core-updates.</a><span class='msg-avail'>...<span class='msg-tooltip'>Conflicts:
	gnu/local.mk
	gnu/packages/build-tools.scm
	gnu/packages/certs.scm
	gnu/packages/check.scm
	gnu/packages/compression.scm
	gnu/packages/cups.scm
	gnu/packages/fontutils.scm
	gnu/packages/gnuzilla.scm
	gnu/packages/guile.scm
	gnu/packages/ibus.scm
	gnu/packages/image-processing.scm
	gnu/packages/linux.scm
	gnu/packages/music.scm
	gnu/packages/nss.scm
	gnu/packages/pdf.scm
	gnu/packages/python-xyz.scm
	gnu/packages/qt.scm
	gnu/packages/ruby.scm
	gnu/packages/shells.scm
	gnu/packages/tex.scm
	gnu/packages/video.scm
	gnu/packages/vulkan.scm
	gnu/packages/web.scm
	gnu/packages/webkit.scm
	gnu/packages/wm.scm
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2023-03-24 21:40:00 -0400'>2023-03-24</span></td><td><a href='/guix/commit/gnu/packages/xiph.scm?id=c1a2e26b28ab2a2b2cb0b0c6ca46da93efe97948'>gnu: speexdsp: Update to 1.2.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/xiph.scm (speexdsp): Update to 1.2.1.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2023-02-07 09:14:13 -0500'>2023-02-07</span></td><td><a href='/guix/commit/gnu/packages/xiph.scm?id=31dac1f0fb3d85dd4d3e57a878b87216d4ca3e40'>gnu: speex: Update to 1.2.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/xiph.scm (speex): Update to 1.2.1.
</span></span></td><td>Maxim Cournoyer</td></tr>