diff --git a/ChangeLog b/ChangeLog
index d474155df7..61107c67fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2023-01-22  Paul Eggert  <eggert@cs.ucla.edu>
+
+	sigsegv, vma-iter: port to Solaris 10
+	On this platform, <sys/types.h> does not define off_t if neither
+	_LP64 nor _FILE_OFFSET_BITS is defined, which can happen if we
+	#undef _FILE_OFFSET_BITS.  This became a problem with the new way
+	of doing stdbool, since config.h now includes <stdbool.h>, and
+	Solaris 10 <stdbool.h> includes <sys/feature_tests.h> which
+	arranges for _FILE_OFFSET_BITS to always be defined (if only to 32),
+	which <sys/types.h> assumes.
+	* lib/stackvma.c, lib/vma-iter.c (_FILE_OFFSET_BITS) [__sun && !_LP64]:
+	Define to 32 instead of leaving undefined.
+
 2023-01-21  Bruno Haible  <bruno@clisp.org>
 
 	login_tty: Ensure declaration in <utmp.h>.
diff --git a/lib/stackvma.c b/lib/stackvma.c
index 4408ca8e15..1224b7b07c 100644
--- a/lib/stackvma.c
+++ b/lib/stackvma.c
@@ -22,6 +22,7 @@
 /* On Solaris in 32-bit mode, when gnulib module 'largefile' is in use,
    prevent a compilation error
      "Cannot use procfs in the large file compilation environment"
+   while also preventing <sys/types.h> from not defining off_t.
    On Android, when targeting Android 4.4 or older with a GCC toolchain,
    prevent a compilation error
      "error: call to 'mmap' declared with attribute error: mmap is not
@@ -30,7 +31,11 @@
       switch to Clang."
    The files that we access in this compilation unit are less than 2 GB
    large.  */
-#if defined __sun || defined __ANDROID__
+#if defined __sun && !defined _LP64 && _FILE_OFFSET_BITS == 64
+# undef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 32
+#endif
+#ifdef __ANDROID__
 # undef _FILE_OFFSET_BITS
 #endif
 
diff --git a/lib/vma-iter.c b/lib/vma-iter.c
index ccb221d273..2584d5ec34 100644
--- a/lib/vma-iter.c
+++ b/lib/vma-iter.c
@@ -20,6 +20,7 @@
 /* On Solaris in 32-bit mode, when gnulib module 'largefile' is in use,
    prevent a compilation error
      "Cannot use procfs in the large file compilation environment"
+   while also preventing <sys/types.h> from not defining off_t.
    On Android, when targeting Android 4.4 or older with a GCC toolchain,
    prevent a compilation error
      "error: call to 'mmap' declared with attribute error: mmap is not
@@ -28,7 +29,11 @@
       switch to Clang."
    The files that we access in this compilation unit are less than 2 GB
    large.  */
-#if defined __sun || defined __ANDROID__
+#if defined __sun && !defined _LP64 && _FILE_OFFSET_BITS == 64
+# undef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 32
+#endif
+#ifdef __ANDROID__
 # undef _FILE_OFFSET_BITS
 #endif