Add -nodevicespecs option for avr.

gcc/
	Add -nodevicespecs option for avr.

	PR target/93182
	* config/avr/avr.opt (-nodevicespecs): New driver option.
	* config/avr/driver-avr.c (avr_devicespecs_file): Only issue
	"-specs=device-specs/..." if that option is not set.
	* doc/invoke.texi (AVR Options) <-nodevicespecs>: Document.

From-SVN: r279995

gcc/ChangeLog

 2020-01-08  Georg-Johann Lay  <avr@gjlay.de>
 
-	Implement 64-bit double functions.
+	Add -nodevicespecs option for avr.
+
+	PR target/93182
+	* config/avr/avr.opt (-nodevicespecs): New driver option.
+	* config/avr/driver-avr.c (avr_devicespecs_file): Only issue
+	"-specs=device-specs/..." if that option is not set.
+	* doc/invoke.texi (AVR Options) <-nodevicespecs>: Document.
+
+2020-01-08  Georg-Johann Lay  <avr@gjlay.de>
+
+	Implement 64-bit double functions for avr.
 
 	PR target/92055
 	* config.gcc (tm_defines) [target=avr]: Support --with-libf7,

gcc/config/avr/avr.opt

@@ -127,6 +127,10 @@ nodevicelib
 Driver Target Report RejectNegative
 Do not link against the device-specific library lib<MCU>.a.
 
+nodevicespecs
+Driver Target Report RejectNegative
+Do not use the device-specific specs file device-specs/specs-<MCU>.
+
 Enum
 Name(avr_bits_e) Type(int)
 Available BITS selections:

gcc/config/avr/driver-avr.c

@@ -26,8 +26,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "diagnostic.h"
 #include "tm.h"
 
-// Remove -nodevicelib from the command line if not needed
-#define X_NODEVLIB "%<nodevicelib"
+// Remove -nodevicelib and -nodevicespecs from the command line if not needed.
+#define X_NODEVLIB "%<nodevicelib %<nodevicespecs"
 
 static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
 
@@ -102,8 +102,8 @@ avr_devicespecs_file (int argc, const char **argv)
         return X_NODEVLIB;
       }
 
-  return concat ("-specs=device-specs", dir_separator_str, "specs-",
-                 mmcu, "%s"
+  return concat ("%{!nodevicespecs:-specs=device-specs", dir_separator_str,
+				 "specs-", mmcu, "%s} %<nodevicespecs"
 #if defined (WITH_AVRLIBC)
                  " %{mmcu=avr*:" X_NODEVLIB "} %{!mmcu=*:" X_NODEVLIB "}",
 #else