diff --git a/configure.ac b/configure.ac
index 4f03e74cdf65b..36bfc9e020459 100644
--- a/configure.ac
+++ b/configure.ac
@@ -416,6 +416,7 @@ dnl Then headers.
 dnl ----------------------------------------------------------------------------
 
 dnl QNX requires unix.h to allow functions in libunix to work properly.
+dnl locale.h is checked for supporting old code in extensions such as imagick.
 AC_CHECK_HEADERS([ \
 inttypes.h \
 stdint.h \
@@ -440,7 +441,6 @@ netdb.h \
 poll.h \
 pwd.h \
 resolv.h \
-signal.h \
 strings.h \
 syslog.h \
 sysexits.h \
@@ -642,7 +642,6 @@ statfs \
 statvfs \
 std_syslog \
 strcasecmp \
-strerror \
 strfmon \
 strnlen \
 strptime \
diff --git a/win32/build/config.w32.h.in b/win32/build/config.w32.h.in
index 1aeea7b62975e..7a12baec1b800 100644
--- a/win32/build/config.w32.h.in
+++ b/win32/build/config.w32.h.in
@@ -62,7 +62,6 @@
 #undef HAVE_FLOCK
 #define HAVE_ALLOCA 1
 #undef HAVE_SYS_TIME_H
-#define HAVE_SIGNAL_H 1
 #undef HAVE_STRUCT_STAT_ST_BLKSIZE
 #undef HAVE_STRUCT_STAT_ST_BLOCKS
 #define HAVE_STRUCT_STAT_ST_RDEV 1
@@ -80,7 +79,6 @@
 #endif
 #define HAVE_SHUTDOWN 1
 #define HAVE_STRCASECMP 1
-#define HAVE_STRERROR 1
 #define HAVE_TEMPNAM 1
 #define HAVE_UTIME 1
 #undef HAVE_DIRENT_H