diff --git a/ChangeLog b/ChangeLog
index f63f01739e..4f1ef82c51 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-23  Gabriel F. T. Gomes  <gftg@linux.vnet.ibm.com>
+
+	* sysdeps/ieee754/float128/Makefile (CFLAGS-strfromf128.c): Add
+	$(libio-mtsafe) to get the value of IO_MTSAFE_IO.
+
 2017-06-23  Gabriel F. T. Gomes  <gftg@linux.vnet.ibm.com>
 
 	* manual/libm-err-tab.pl (@all_floats, %suffices, parse_ulps):
diff --git a/sysdeps/ieee754/float128/Makefile b/sysdeps/ieee754/float128/Makefile
index 166e630290..571a841809 100644
--- a/sysdeps/ieee754/float128/Makefile
+++ b/sysdeps/ieee754/float128/Makefile
@@ -1,6 +1,10 @@
 ifeq ($(subdir),stdlib)
 routines += float1282mpn strfromf128
 routines += strtof128 strtof128_l strtof128_nan mpn2float128
+
+# The strfrom class of functions call __printf_fp in order to convert the
+# floating-point value to characters.  This requires the value of IO_MTSAFE_IO.
+CFLAGS-strfromf128.c += $(libio-mtsafe)
 endif
 
 ifeq ($(subdir),wcsmbs)