diff --git a/configure/CONFIG_BASE b/configure/CONFIG_BASE
index 7c545c92d..757bd35e3 100644
--- a/configure/CONFIG_BASE
+++ b/configure/CONFIG_BASE
@@ -71,7 +71,7 @@ FULLPATHNAME               = $(PERL) $(TOOLS)/fullPathName.pl
 
 #-------------------------------------------------------
 # tools for installing libraries and products
-INSTALL_QUIETLY := $(if $(findstring s,$(MFLAGS)),-q,)
+INSTALL_QUIETLY := $(if $(filter -s,$(MFLAGS)),-q,)
 INSTALL = $(PERL) $(TOOLS)/installEpics.pl $(INSTALL_QUIETLY)
 INSTALL_PRODUCT = $(INSTALL)
 INSTALL_LIBRARY = $(INSTALL)
diff --git a/configure/CONFIG_COMMON b/configure/CONFIG_COMMON
index 43f4866d7..471226db5 100644
--- a/configure/CONFIG_COMMON
+++ b/configure/CONFIG_COMMON
@@ -80,9 +80,9 @@ COMMON_DIR = ../O.Common
 IOCS_APPL_TOP               = $(shell $(FULLPATHNAME) $(INSTALL_LOCATION))
 
 #-------------------------------------------------------
-# Make echo output - suppress echoing if make's '-s' flag is set
+# Make echo output - suppress echoing if '-s' flag was given
 NOP = :
-ECHO = @$(if $(findstring s,$(MFLAGS)),$(NOP),echo)
+ECHO = @$(if $(filter -s,$(MFLAGS)),$(NOP),echo)
 
 #-------------------------------------------------------
 ifdef T_A
diff --git a/configure/os/CONFIG.Common.RTEMS b/configure/os/CONFIG.Common.RTEMS
index 8f65b08f7..03f07231d 100644
--- a/configure/os/CONFIG.Common.RTEMS
+++ b/configure/os/CONFIG.Common.RTEMS
@@ -72,7 +72,7 @@ CPPFLAGS += $($(BUILD_CLASS)_CPPFLAGS) $(POSIX_CPPFLAGS) $(OPT_CPPFLAGS)\
  $(USR_CPPFLAGS) $(CMD_CPPFLAGS) $(ARCH_DEP_CPPFLAGS) $(OP_SYS_CPPFLAGS)\
  $(OP_SYS_INCLUDE_CPPFLAGS) $(CODE_CPPFLAGS)
 
-ECHO = @$(if $(findstring s,$(MFLAGS)),$(NOP),echo)
+ECHO = @$(if $(filter -s,$(MFLAGS)),$(NOP),echo)
 
 #--------------------------------------------------
 # Although RTEMS uses gcc, it wants to use gcc its own way