libm/newlib: Add arch-specific source code first to CSRCS

Source code under `newlib/newlib/newlib/libm/machine/$(ARCH)/*.c`
should be added before common source code from `../../common/*.c`.
Take `newlib/newlib/newlib/libm/machine/riscv/s_fma.c` as an
example:

```

double
fma (double x, double y, double z)
{
        double result;
        asm ("fmadd.d %0, %1, %2, %3" : "=f" (result) : "f" (x), "f" (y), "f" (z));
        return result;
}

```

Note that the common `s_fma.c` will be included by the source file
directly. The order of adding the files to CSRCS matters here.

Although the CMake-based build system does not have the same build
problem of including the a source-file with the same in the wrong
order, this commit also changes the order of inclusion for CMake
too to keep it consistent.

libs/libm/newlib/CMakeLists.txt

@@ -87,11 +87,12 @@ if(CONFIG_LIBM_NEWLIB)
     set(ARCH_DIR ${CONFIG_ARCH})
   endif()
 
-  file(GLOB_RECURSE COMMON_CSRCS ${NEWLIB_DIR}/newlib/libm/common/*.c)
-  file(GLOB_RECURSE COMPLEX_CSRCS ${NEWLIB_DIR}/newlib/libm/complex/*.c)
   file(GLOB_RECURSE ARCH_CSRCS
        ${NEWLIB_DIR}/newlib/libm/machine/${ARCH_DIR}/*.c)
 
+  file(GLOB_RECURSE COMMON_CSRCS ${NEWLIB_DIR}/newlib/libm/common/*.c)
+  file(GLOB_RECURSE COMPLEX_CSRCS ${NEWLIB_DIR}/newlib/libm/complex/*.c)
+
   if(CONFIG_ARCH_X86_64)
     file(GLOB_RECURSE ARCH_CSRCS ${NEWLIB_DIR}/newlib/libm/fenv/*.c)
   endif()

libs/libm/newlib/Make.defs

@@ -58,14 +58,6 @@ $(TOPDIR)/include/newlib: newlib/newlib
 
 context:: $(TOPDIR)/include/newlib
 
-CSRCS += $(wildcard newlib/newlib/newlib/libm/common/*.c)
-CSRCS += $(wildcard newlib/newlib/newlib/libm/complex/*.c)
-
-VPATH += :newlib/newlib/newlib/libm/common
-VPATH += :newlib/newlib/newlib/libm/complex
-DEPPATH += --dep-path newlib/newlib/newlib/libm/common
-DEPPATH += --dep-path newlib/newlib/newlib/libm/complex
-
 ifeq ($(CONFIG_ARCH_ARM),y)
   ARCH = arm
 else ifeq ($(CONFIG_ARCH_ARM64),y)
@@ -88,6 +80,13 @@ CSRCS += $(wildcard newlib/newlib/newlib/libm/machine/$(ARCH)/*.c)
 VPATH += :newlib/newlib/newlib/libm/machine/$(ARCH)
 DEPPATH += --dep-path newlib/newlib/newlib/libm/machine/$(ARCH)
 
+CSRCS += $(wildcard newlib/newlib/newlib/libm/common/*.c)
+CSRCS += $(wildcard newlib/newlib/newlib/libm/complex/*.c)
+
+VPATH += :newlib/newlib/newlib/libm/common
+VPATH += :newlib/newlib/newlib/libm/complex
+DEPPATH += --dep-path newlib/newlib/newlib/libm/common
+DEPPATH += --dep-path newlib/newlib/newlib/libm/complex
 
 ifeq ($(CONFIG_ARCH_X86_64),y)
 CSRCS += $(wildcard newlib/newlib/newlib/libm/fenv/*.c)