poco: Fix build on risc-v

Patch fixes following error

TOPDIR/build/tmp/work/riscv64-yoe-linux-musl/poco/1.9.4-r0/git/Foundation/src/utils.h:76:2: error: Target architecture was not detected as supported by Double-Conversion.
 ^
1 error generated.

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-support/poco/poco/0001-riscv-Enable-double-operations-when-using-double-flo.patch

@@ -0,0 +1,28 @@
+From 589a5442a841b156a1890bc2d26e7a5103e2f672 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Fri, 1 Nov 2019 17:53:50 -0700
+Subject: [PATCH] riscv: Enable double operations when using double float abi
+
+Upstream-Status: Submitted [https://github.com/pocoproject/poco/pull/2825]
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ Foundation/src/utils.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/Foundation/src/utils.h b/Foundation/src/utils.h
+index 69cea1aca..ff7a5c9ce 100644
+--- a/Foundation/src/utils.h
++++ b/Foundation/src/utils.h
+@@ -63,7 +63,8 @@
+     defined(__SH4__) || defined(__alpha__) || \
+     defined(_MIPS_ARCH_MIPS32R2) || \
+     defined(__AARCH64EL__) || \
+-    defined(nios2) || defined(__nios2) || defined(__nios2__)
++    defined(nios2) || defined(__nios2) || defined(__nios2__) || \
++    (defined(__riscv) && defined(__riscv_float_abi_double))
+ #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
+ #elif defined(_M_IX86) || defined(__i386__) || defined(__i386)
+ #if defined(_WIN32)
+-- 
+2.23.0
+

meta-oe/recipes-support/poco/poco_1.9.4.bb

@@ -11,6 +11,7 @@ DEPENDS = "libpcre zlib"
 SRC_URI = " \
     git://github.com/pocoproject/poco.git;branch=poco-${PV} \
     file://0001-Don-t-try-to-install-non-existing-Encodings-testsuit.patch \
+    file://0001-riscv-Enable-double-operations-when-using-double-flo.patch \
     file://run-ptest \
    "
 SRCREV = "b95393dcc3640807838e8323b4e600e54d2e8116"