build: don't link against libm.so

There are very few places where we actually use floating point
or #include <math.h>.

Drop that library, although we very likely still get it as indirect
dependency (e.g. on my system it is still dragged in by libsystemd.so,
libudev.so and libnl-3.so).

Makefile.am

@@ -1473,7 +1473,6 @@ src_libNetworkManager_la_LIBADD = \
 	$(SYSTEMD_LOGIN_LIBS) \
 	$(LIBNDP_LIBS) \
 	$(DL_LIBS) \
-	$(LIBM) \
 	$(SELINUX_LIBS) \
 	$(LIBAUDIT_LIBS) \
 	$(LIBPSL_LIBS) \
@@ -1546,8 +1545,7 @@ src_nm_iface_helper_LDADD = \
 	$(LIBUDEV_LIBS) \
 	$(LIBNL_LIBS) \
 	$(LIBNDP_LIBS) \
-	$(DL_LIBS) \
+	$(DL_LIBS)
-	$(LIBM)
 
 src_nm_iface_helper_LDFLAGS = \
 	-Wl,--version-script="$(srcdir)/linker-script-binary.ver"

configure.ac

@@ -274,11 +274,6 @@ else
 	AC_DEFINE(HAVE_VLAN_FLAG_LOOSE_BINDING, 0, [Define if you have VLAN_FLAG_LOOSE_BINDING])
 fi
 
-dnl
-dnl Checks for libm - needed for pow()
-dnl
-LT_LIB_M
-
 dnl
 dnl Checks for libdl - on certain platforms its part of libc
 dnl

libnm-core/nm-property-compare.c

@@ -23,7 +23,6 @@
 #include "nm-default.h"
 
 #include <string.h>
-#include <math.h>
 #include <netinet/in.h>
 
 #include "nm-property-compare.h"

libnm-util/nm-param-spec-specialized.c

@@ -30,7 +30,6 @@ struct _NMParamSpecSpecialized {
 };
 
 #include <string.h>
-#include <math.h>
 #include <netinet/in.h>
 #include <dbus/dbus-glib.h>
 
@@ -157,15 +156,19 @@ _gvalues_compare_fixed (const GValue *value1, const GValue *value2)
 	case G_TYPE_FLOAT: {
 		gfloat val1 = g_value_get_float (value1);
 		gfloat val2 = g_value_get_float (value2);
+		float diff = val1 - val2;
+
 		/* Can't use == or != here due to inexactness of FP */
-		if (fabsf (val1 - val2) > FLOAT_FACTOR)
+		if (diff > FLOAT_FACTOR || diff < -FLOAT_FACTOR)
 			ret = val1 < val2 ? -1 : val1 > val2;
 		break;
 	}
 	case G_TYPE_DOUBLE: {
 		gdouble val1 = g_value_get_double (value1);
 		gdouble val2 = g_value_get_double (value2);
-		if (fabs (val1 - val2) > FLOAT_FACTOR)
+		double diff = val1 - val2;
+
+		if (diff > FLOAT_FACTOR || diff < -FLOAT_FACTOR)
 			ret = val1 < val2 ? -1 : val1 > val2;
 		break;
 	}

src/platform/wifi/wifi-utils-nl80211.c

@@ -27,7 +27,6 @@
 #include <sys/ioctl.h>
 #include <net/ethernet.h>
 #include <unistd.h>
-#include <math.h>
 #include <netlink/netlink.h>
 #include <netlink/msg.h>
 #include <linux/nl80211.h>

src/platform/wifi/wifi-utils-wext.c

@@ -26,7 +26,6 @@
 #include <sys/ioctl.h>
 #include <net/ethernet.h>
 #include <unistd.h>
-#include <math.h>
 
 #include "wifi-utils-private.h"
 #include "wifi-utils-wext.h"
@@ -79,7 +78,7 @@ struct iw_range_with_scan_capa
 	} G_STMT_END
 
 static guint32
-iw_freq_to_uint32 (struct iw_freq *freq)
+iw_freq_to_uint32 (const struct iw_freq *freq)
 {
 	if (freq->e == 0) {
 		/* Some drivers report channel not frequency.  Convert to a
@@ -90,8 +89,7 @@ iw_freq_to_uint32 (struct iw_freq *freq)
 		else if (freq->m == 14)
 			return 2484;
 	}
-
+	return (guint32) ((((double) freq->m) * nm_utils_10pow (freq->e)) / 1000000.0);
-	return (guint32) (((double) freq->m) * pow (10, freq->e) / 1000000);
 }
 
 static void