picolibc: Add support for version 1.7.1

Since 1.6.2, picolibc has had two releases - 1.7 and 1.7.1. Here are
the release notes from those versions.

 1. Add __cxa_atexit implementation to 'picoexit' path as required by
    C++

 2. Fix lack of 'hh' support in integer-only tinystdio printf path.

 3. Fix tinystdio __file flag initialization for C++ apps

 1. Merge libc and libm into a single library. Having them split
    doesn't offer any advantages while requiring that applications add
    '-lm' to link successfully. Having them merged allows use of libm
    calls from libc code.

 2. Add hex float format to *printf, *scanf and strto{d,f,ld}. This is
    required for C99 support.

 3. Unify strto{d,f,ld} and *scanf floating point parsing code. This
    ensures that the library is consistent in how floats are parsed.

 4. Make strto{d,f,ld} set errno to ERANGE on overflow/underflow,
    including when the result is a subnormal number.

Signed-off-by: Keith Packard <keithp@keithp.com>

packages/picolibc/1.7.1/chksum

@@ -0,0 +1,4 @@
+md5 picolibc-1.7.1.tar.xz c35296fa0eeb625f6664ae80ea252b09
+sha1 picolibc-1.7.1.tar.xz 3b1948feee5d1c5325fbc81963e6d5480aa9b927
+sha256 picolibc-1.7.1.tar.xz 6301c22c385d299c4fbb36e23b55a4e65b7a14952ee62c8638a535063a310857
+sha512 picolibc-1.7.1.tar.xz 03bf635841e8f96e8a675162693f7275f907ae4dd97e51c962d969c2b9c721240625c0e7d9582a41804913c36c1db15844ccabd0926ceda67ffb169b29a5d5f6

packages/picolibc/package.desc

@@ -1,6 +1,6 @@
 origin='keithp.com'
 repository='git https://github.com/picolibc/picolibc.git'
-milestones='1.4 1.5 1.6'
+milestones='1.4 1.5 1.6 1.7'
 relevantpattern='*.*|.*. *.*|.'
 archive_formats='.tar.xz'
 mirrors='https://github.com/picolibc/picolibc/releases/download/${CT_PICOLIBC_VERSION}'