dc: conditionalize parts which require libm

editors/Config.in

@@ -14,7 +14,7 @@ config AWK
 
 config FEATURE_AWK_MATH
 	bool "Enable math functions (requires libm)"
-	default y
+	default n
 	depends on AWK
 	help
 	  Enable math functions of the Awk programming language.

miscutils/Config.in

@@ -138,6 +138,14 @@ config DC
 	  Dc is a reverse-polish desk calculator which supports unlimited
 	  precision arithmetic.
 
+config FEATURE_DC_LIBM
+	bool "Enable power and exp functions (requires libm)"
+	default n
+	depends on DC
+	help
+	  Enable power and exp functions.
+	  NOTE: This will require libm to be present for linking.
+
 config DEVFSD
 	bool "devfsd (obsolete)"
 	default n

miscutils/dc.c

@@ -53,12 +53,14 @@ static void mul(void)
 	push(pop() * pop());
 }
 
+#if ENABLE_FEATURE_DC_LIBM
 static void power(void)
 {
 	double topower = pop();
 
 	push(pow(pop(), topower));
 }
+#endif
 
 static void divide(void)
 {
@@ -137,9 +139,11 @@ static const struct op operators[] = {
 	{"mul", mul},
 	{"/",   divide},
 	{"div", divide},
+#if ENABLE_FEATURE_DC_LIBM
 	{"**",  power},
 	{"exp", power},
 	{"pow", power},
+#endif
 	{"%",   mod},
 	{"mod", mod},
 	{"and", and},

shell/ash_test/ash-standalone/noexec_gets_no_env.right

@@ -1,2 +1,4 @@
 VAR7=VAL
 0
+VAR8=VAL
+0

shell/ash_test/ash-standalone/noexec_gets_no_env.tests

@@ -1,3 +1,5 @@
 export VAR7=VAL
 env | grep ^VAR7=
 echo $?
+VAR8=VAL env | grep ^VAR8=
+echo $?