Better removing unnecessary flags using `build_unflags` option // Resolve #698

platformio/builder/scripts/basearm.py

@@ -40,8 +40,7 @@ env.Replace(
         "-fdata-sections",
         "-Wall",
         "-mthumb",
-        "-mcpu=${BOARD_OPTIONS['build']['cpu']}",
-        "-nostdlib"
+        "-mcpu=${BOARD_OPTIONS['build']['cpu']}"
     ],
 
     CXXFLAGS=[
@@ -57,7 +56,9 @@ env.Replace(
         "-Os",
         "-Wl,--gc-sections,--relax",
         "-mthumb",
-        "-mcpu=${BOARD_OPTIONS['build']['cpu']}"
+        "-mcpu=${BOARD_OPTIONS['build']['cpu']}",
+        "-nostdlib",
+        "-nostartfiles"
     ],
 
     LIBS=["c", "gcc", "m"],

platformio/builder/scripts/espressif.py

@@ -71,8 +71,7 @@ env.Replace(
         "-Wpointer-arith",
         "-Wno-implicit-function-declaration",
         "-Wl,-EL",
-        "-fno-inline-functions",
-        "-nostdlib"
+        "-fno-inline-functions"
     ],
 
     CCFLAGS=[
@@ -82,8 +81,7 @@ env.Replace(
         "-falign-functions=4",
         "-U__STRICT_ANSI__",
         "-ffunction-sections",
-        "-fdata-sections",
-        "-MMD"  # output dependancy info
+        "-fdata-sections"
     ],
 
     CXXFLAGS=[

platformio/builder/scripts/frameworks/mbed.py

@@ -264,13 +264,12 @@ env.Replace(
 )
 
 # restore external build flags
-env.ProcessFlags([
-    env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags")
-])
+env.ProcessFlags(
+    env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags"))
 # remove base flags
 env.ProcessUnFlags(env.get("BUILD_UNFLAGS"))
 # apply user flags
-env.ProcessFlags([env.get("BUILD_FLAGS")])
+env.ProcessFlags(env.get("BUILD_FLAGS"))
 
 # Hook for K64F and K22F
 if board_type in ("frdm_k22f", "frdm_k64f"):

platformio/builder/scripts/ststm32.py

@@ -66,11 +66,6 @@ env.Append(
     ],
 
     LIBS=["stdc++", "nosys"],
-
-    LINKFLAGS=[
-        "-nostartfiles",
-        "-nostdlib"
-    ]
 )
 
 #

platformio/builder/scripts/titiva.py

@@ -31,13 +31,6 @@ env.Replace(
     UPLOADCMD='"$UPLOADER" $SOURCES'
 )
 
-env.Append(
-    LINKFLAGS=[
-        "-nostartfiles",
-        "-nostdlib"
-    ]
-)
-
 #
 # Target: Build executable and linkable firmware
 #