https://bugs.gentoo.org/909422
https://github.com/randombit/botan/commit/3f87e1eef7dbfe231d833ffbf06f7a85b070b600 (cherry-picked getentropy.cpp bit)
https://github.com/randombit/botan/commit/562ea8da8ab34985b4b3dfefc1bea57829213ace

--- a/src/lib/entropy/getentropy/getentropy.cpp
+++ b/src/lib/entropy/getentropy/getentropy.cpp
@@ -10,8 +10,8 @@
 #if defined(BOTAN_TARGET_OS_IS_OPENBSD) || defined(BOTAN_TARGET_OS_IS_FREEBSD) || defined(BOTAN_TARGET_OS_IS_SOLARIS)
    #include <unistd.h>
 #else
-   #include <sys/types.h> // older macOS needs this before sys/random.h
    #include <sys/random.h>
+   #include <sys/types.h>  // older macOS needs this before sys/random.h
 #endif
 
 namespace Botan {
@@ -21,16 +21,14 @@ namespace Botan {
 * buffer size is limited to 256 bytes.  On OpenBSD this does neither
 * block nor fail.
 */
-size_t Getentropy::poll(RandomNumberGenerator& rng)
-   {
+size_t Getentropy::poll(RandomNumberGenerator& rng) {
    secure_vector<uint8_t> buf(256);
 
-   if(::getentropy(buf.data(), buf.size()) == 0)
-      {
+   if(::getentropy(buf.data(), buf.size()) == 0) {
       rng.add_entropy(buf.data(), buf.size());
       return buf.size() * 8;
-      }
+   }
 
    return 0;
-   }
 }
+}  // namespace Botan

From 562ea8da8ab34985b4b3dfefc1bea57829213ace Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Mon, 29 May 2023 10:10:54 -0400
Subject: [PATCH] Clean up getentropy includes

--- a/src/lib/entropy/getentropy/getentropy.cpp
+++ b/src/lib/entropy/getentropy/getentropy.cpp
@@ -6,12 +6,11 @@
 */
 
 #include <botan/internal/getentropy.h>
+#include <unistd.h>
 
-#if defined(BOTAN_TARGET_OS_IS_OPENBSD) || defined(BOTAN_TARGET_OS_IS_FREEBSD) || defined(BOTAN_TARGET_OS_IS_SOLARIS)
-   #include <unistd.h>
-#else
+// macOS and Android include it in sys/random.h instead
+#if __has_include(<sys/random.h>)
    #include <sys/random.h>
-   #include <sys/types.h>  // older macOS needs this before sys/random.h
 #endif
 
 namespace Botan {
@@ -31,4 +30,5 @@ size_t Getentropy::poll(RandomNumberGenerator& rng) {
 
    return 0;
 }
+
 }  // namespace Botan