diff --git a/config/c-compiler.m4 b/config/c-compiler.m4
index 501b74b3a1..780e906ecc 100644
--- a/config/c-compiler.m4
+++ b/config/c-compiler.m4
@@ -2,8 +2,8 @@
 # config/c-compiler.m4
 
 
-# PGAC_C_PRINTF_ARCHETYPE
-# -----------------------
+# PGAC_PRINTF_ARCHETYPE
+# ---------------------
 # Select the format archetype to be used by gcc to check printf-type functions.
 # We prefer "gnu_printf", as that most closely matches the features supported
 # by src/port/snprintf.c (particularly the %m conversion spec).  However,
@@ -93,7 +93,7 @@ undefine([Ac_cachevar])dnl
 
 
 # PGAC_TYPE_128BIT_INT
-# ---------------------
+# --------------------
 # Check if __int128 is a working 128 bit integer type, and if so
 # define PG_INT128_TYPE to that typename, and define ALIGNOF_PG_INT128_TYPE
 # as its alignment requirement.
@@ -282,7 +282,7 @@ fi])# PGAC_C_BUILTIN_CONSTANT_P
 
 
 # PGAC_C_BUILTIN_OP_OVERFLOW
-# -------------------------
+# --------------------------
 # Check if the C compiler understands __builtin_$op_overflow(),
 # and define HAVE__BUILTIN_OP_OVERFLOW if so.
 #
@@ -331,7 +331,7 @@ fi])# PGAC_C_BUILTIN_UNREACHABLE
 
 
 # PGAC_C_COMPUTED_GOTO
-# -----------------------
+# --------------------
 # Check if the C compiler knows computed gotos (gcc extension, also
 # available in at least clang).  If so, define HAVE_COMPUTED_GOTO.
 #
@@ -382,7 +382,7 @@ fi])# PGAC_CHECK_BUILTIN_FUNC
 
 
 # PGAC_PROG_VARCC_VARFLAGS_OPT
-# -----------------------
+# ----------------------------
 # Given a compiler, variable name and a string, check if the compiler
 # supports the string as a command-line option. If it does, add the
 # string to the given variable.
@@ -420,7 +420,7 @@ PGAC_PROG_VARCC_VARFLAGS_OPT(CC, CFLAGS, $1)
 
 
 # PGAC_PROG_CC_VAR_OPT
-# -----------------------
+# --------------------
 # Given a variable name and a string, check if the compiler supports
 # the string as a command-line option. If it does, add the string to
 # the given variable.
@@ -431,7 +431,7 @@ AC_DEFUN([PGAC_PROG_CC_VAR_OPT],
 
 
 # PGAC_PROG_VARCXX_VARFLAGS_OPT
-# -----------------------
+# -----------------------------
 # Given a compiler, variable name and a string, check if the compiler
 # supports the string as a command-line option. If it does, add the
 # string to the given variable.
@@ -461,12 +461,12 @@ undefine([Ac_cachevar])dnl
 
 
 # PGAC_PROG_CXX_CFLAGS_OPT
-# -----------------------
+# ------------------------
 # Given a string, check if the compiler supports the string as a
 # command-line option. If it does, add the string to CXXFLAGS.
 AC_DEFUN([PGAC_PROG_CXX_CFLAGS_OPT],
 [PGAC_PROG_VARCXX_VARFLAGS_OPT(CXX, CXXFLAGS, $1)
-])# PGAC_PROG_CXX_VAR_OPT
+])# PGAC_PROG_CXX_CFLAGS_OPT
 
 
 
@@ -494,7 +494,7 @@ undefine([Ac_cachevar])dnl
 ])# PGAC_PROG_CC_LDFLAGS_OPT
 
 # PGAC_HAVE_GCC__SYNC_CHAR_TAS
-# -------------------------
+# ----------------------------
 # Check if the C compiler understands __sync_lock_test_and_set(char),
 # and define HAVE_GCC__SYNC_CHAR_TAS
 #
@@ -514,7 +514,7 @@ if test x"$pgac_cv_gcc_sync_char_tas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__SYNC_CHAR_TAS
 
 # PGAC_HAVE_GCC__SYNC_INT32_TAS
-# -------------------------
+# -----------------------------
 # Check if the C compiler understands __sync_lock_test_and_set(),
 # and define HAVE_GCC__SYNC_INT32_TAS
 AC_DEFUN([PGAC_HAVE_GCC__SYNC_INT32_TAS],
@@ -530,7 +530,7 @@ if test x"$pgac_cv_gcc_sync_int32_tas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__SYNC_INT32_TAS
 
 # PGAC_HAVE_GCC__SYNC_INT32_CAS
-# -------------------------
+# -----------------------------
 # Check if the C compiler understands __sync_compare_and_swap() for 32bit
 # types, and define HAVE_GCC__SYNC_INT32_CAS if so.
 AC_DEFUN([PGAC_HAVE_GCC__SYNC_INT32_CAS],
@@ -545,7 +545,7 @@ if test x"$pgac_cv_gcc_sync_int32_cas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__SYNC_INT32_CAS
 
 # PGAC_HAVE_GCC__SYNC_INT64_CAS
-# -------------------------
+# -----------------------------
 # Check if the C compiler understands __sync_compare_and_swap() for 64bit
 # types, and define HAVE_GCC__SYNC_INT64_CAS if so.
 AC_DEFUN([PGAC_HAVE_GCC__SYNC_INT64_CAS],
@@ -560,7 +560,7 @@ if test x"$pgac_cv_gcc_sync_int64_cas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__SYNC_INT64_CAS
 
 # PGAC_HAVE_GCC__ATOMIC_INT32_CAS
-# -------------------------
+# -------------------------------
 # Check if the C compiler understands __atomic_compare_exchange_n() for 32bit
 # types, and define HAVE_GCC__ATOMIC_INT32_CAS if so.
 AC_DEFUN([PGAC_HAVE_GCC__ATOMIC_INT32_CAS],
@@ -576,7 +576,7 @@ if test x"$pgac_cv_gcc_atomic_int32_cas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__ATOMIC_INT32_CAS
 
 # PGAC_HAVE_GCC__ATOMIC_INT64_CAS
-# -------------------------
+# -------------------------------
 # Check if the C compiler understands __atomic_compare_exchange_n() for 64bit
 # types, and define HAVE_GCC__ATOMIC_INT64_CAS if so.
 AC_DEFUN([PGAC_HAVE_GCC__ATOMIC_INT64_CAS],
@@ -592,7 +592,7 @@ if test x"$pgac_cv_gcc_atomic_int64_cas" = x"yes"; then
 fi])# PGAC_HAVE_GCC__ATOMIC_INT64_CAS
 
 # PGAC_SSE42_CRC32_INTRINSICS
-# -----------------------
+# ---------------------------
 # Check if the compiler supports the x86 CRC instructions added in SSE 4.2,
 # using the _mm_crc32_u8 and _mm_crc32_u32 intrinsic functions. (We don't
 # test the 8-byte variant, _mm_crc32_u64, but it is assumed to be present if
@@ -623,7 +623,7 @@ undefine([Ac_cachevar])dnl
 
 
 # PGAC_ARMV8_CRC32C_INTRINSICS
-# -----------------------
+# ----------------------------
 # Check if the compiler supports the CRC32C instructions using the __crc32cb,
 # __crc32ch, __crc32cw, and __crc32cd intrinsic functions. These instructions
 # were first introduced in ARMv8 in the optional CRC Extension, and became