5 files changed, 20 insertions, 17 deletions
diff --git a/m4/dpkg-arch.m4 b/m4/dpkg-arch.m4
index 1b240a4..8859289 100644
--- a/m4/dpkg-arch.m4
+++ b/m4/dpkg-arch.m4
@@ -3,7 +3,7 @@
 # Copyright © 2006-2023 Guillem Jover <guillem@debian.org>
 
 # _DPKG_ARCHITECTURE([DEB_VAR], [sh_var])
-# ---------------------------------------
+# ------------------
 # Use dpkg-architecture from the source tree to set sh_var using DEB_VAR for
 # the target architecture, to avoid duplicating its logic.
 AC_DEFUN([_DPKG_ARCHITECTURE], [
@@ -49,7 +49,7 @@ AC_DEFUN([DPKG_OS_TYPE], [
 ])# DPKG_OS_TYPE
 
 # DPKG_ARCHITECTURE
-# ------------------------
+# -----------------
 # Determine the Debian name for the host operating system,
 # sets ARCHITECTURE.
 AC_DEFUN([DPKG_ARCHITECTURE], [
diff --git a/m4/dpkg-compiler.m4 b/m4/dpkg-compiler.m4
index 756af26..cb1063d 100644
--- a/m4/dpkg-compiler.m4
+++ b/m4/dpkg-compiler.m4
@@ -211,7 +211,7 @@ AC_DEFUN([DPKG_COMPILER_OPTIMIZATIONS], [
 ])
 
 # DPKG_TRY_C99([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
-# ------------------------------------------------------
+# ------------
 # Try compiling some C99 code to see whether it works
 AC_DEFUN([DPKG_TRY_C99], [
   AC_COMPILE_IFELSE([
@@ -253,6 +253,10 @@ AC_DEFUN([DPKG_TRY_C99], [
 
 	/* Magic __func__ variable. */
 	printf("%s", __func__);
+
+#if __STDC_VERSION__ < 199901L
+#error "Requires C99"
+#endif
     ]])
   ], [$1], [$2])dnl
 ])# DPKG_TRY_C99
@@ -261,11 +265,11 @@ AC_DEFUN([DPKG_TRY_C99], [
 # ----------
 # Check whether the compiler can do C99
 AC_DEFUN([DPKG_C_C99], [
-  AC_CACHE_CHECK([whether $CC supports C99 features], [dpkg_cv_c99], [
+  AC_CACHE_CHECK([whether $CC supports C99], [dpkg_cv_c99], [
     DPKG_TRY_C99([dpkg_cv_c99=yes], [dpkg_cv_c99=no])
   ])
   AS_IF([test "x$dpkg_cv_c99" != "xyes"], [
-    AC_CACHE_CHECK([for $CC option to accept C99 features], [dpkg_cv_c99_arg], [
+    AC_CACHE_CHECK([for $CC option to accept C99], [dpkg_cv_c99_arg], [
       dpkg_cv_c99_arg=none
       dpkg_save_CC="$CC"
       for arg in "-std=gnu99" "-std=c99" "-c99" "-AC99" "-xc99=all" \
@@ -282,13 +286,11 @@ AC_DEFUN([DPKG_C_C99], [
     ])
     AS_IF([test "x$dpkg_cv_c99_arg" != "xnone"], [
       CC="$CC $dpkg_cv_c99_arg"
-      dpkg_cv_c99=1
+      dpkg_cv_c99=yes
     ])
   ])
-  AS_IF([test "x$dpkg_cv_c99" = "xyes"], [
-    AC_DEFINE([HAVE_C99], 1, [Define to 1 if the compiler supports C99.])
-  ], [
-    AC_MSG_ERROR([unsupported required C99 extensions])
+  AS_IF([test "x$dpkg_cv_c99" != "xyes"], [
+    AC_MSG_ERROR([unsupported required C99])
   ])
 ])# DPKG_C_C99
 
@@ -302,6 +304,10 @@ AC_DEFUN([DPKG_TRY_CXX11], [
     ]], [[
 	// Null pointer keyword.
 	void *ptr = nullptr;
+
+#if __cplusplus < 201103L
+#error "Requires C++11"
+#endif
     ]])
   ], [$1], [$2])
   AC_LANG_POP([C++])dnl
@@ -333,7 +339,4 @@ AC_DEFUN([DPKG_CXX_CXX11], [
       dpkg_cv_cxx11=yes
     ])
   ])
-  AS_IF([test "x$dpkg_cv_cxx11" = "xyes"], [
-    AC_DEFINE([HAVE_CXX11], 1, [Define to 1 if the compiler supports C++11.])
-  ])[]dnl
 ])# DPKG_CXX_CXX11
diff --git a/m4/dpkg-funcs.m4 b/m4/dpkg-funcs.m4
index c480c10..22002b5 100644
--- a/m4/dpkg-funcs.m4
+++ b/m4/dpkg-funcs.m4
@@ -77,7 +77,7 @@ AC_DEFUN([DPKG_FUNC_FSYNC_DIR], [
 ])
 
 # DPKG_FUNC_C99_SNPRINTF
-# -----------------------
+# ----------------------
 # Define HAVE_C99_SNPRINTF if we have C99 snprintf family semantics
 AC_DEFUN([DPKG_FUNC_C99_SNPRINTF], [
   AC_CACHE_CHECK([for C99 snprintf functions], [dpkg_cv_c99_snprintf], [
diff --git a/m4/dpkg-libs.m4 b/m4/dpkg-libs.m4
index 9ef5263..21858a8 100644
--- a/m4/dpkg-libs.m4
+++ b/m4/dpkg-libs.m4
@@ -26,7 +26,7 @@ AC_DEFUN([DPKG_LIB_MD], [
 ])# DPKG_LIB_MD
 
 # DPKG_WITH_COMPRESS_LIB(NAME, HEADER, FUNC)
-# -------------------------------------------------
+# ----------------------
 # Check for availability of a compression library.
 AC_DEFUN([DPKG_WITH_COMPRESS_LIB], [
   AC_ARG_VAR(AS_TR_CPP([$1_LIBS]), [linker flags for $1 library])
@@ -109,7 +109,7 @@ AC_DEFUN([DPKG_LIB_LZMA], [
 ])# DPKG_LIB_LZMA
 
 # DPKG_LIB_ZSTD
-# ------------
+# -------------
 # Check for zstd library.
 AC_DEFUN([DPKG_LIB_ZSTD], [
   DPKG_WITH_COMPRESS_LIB([zstd], [zstd.h], [ZSTD_compressStream2])
diff --git a/m4/dpkg-progs.m4 b/m4/dpkg-progs.m4
index cd18ba1..b00f1aa 100644
--- a/m4/dpkg-progs.m4
+++ b/m4/dpkg-progs.m4
@@ -114,7 +114,7 @@ AC_DEFUN([DPKG_PROG_PO4A], [
 ])# DPKG_PROG_PO4A
 
 # DPKG_PROG_POD2MAN
-# --------------
+# -----------------
 AC_DEFUN([DPKG_PROG_POD2MAN], [
   AC_ARG_VAR([POD2MAN], [pod2man program])
   AC_CHECK_PROGS([POD2MAN], [pod2man])