https://ssl.icu-project.org/trac/ticket/9286
https://ssl.icu-project.org/trac/ticket/9365
https://ssl.icu-project.org/trac/changeset/31780
https://ssl.icu-project.org/trac/changeset/31971
https://ssl.icu-project.org/trac/changeset/32020
https://ssl.icu-project.org/trac/changeset/32023

--- common/putilimp.h
+++ common/putilimp.h
@@ -117,6 +117,8 @@
 #   define U_TIMEZONE __timezone
 #elif U_PLATFORM_USES_ONLY_WIN32_API
 #   define U_TIMEZONE _timezone
+#elif U_PLATFORM == U_PF_BSD && !defined(__NetBSD__)
+   /* not defined */
 #elif U_PLATFORM == U_PF_OS400
    /* not defined */
 #else
--- common/unicode/platform.h
+++ common/unicode/platform.h
@@ -131,7 +131,7 @@
 #   include <android/api-level.h>
 #elif defined(linux) || defined(__linux__) || defined(__linux)
 #   define U_PLATFORM U_PF_LINUX
-#elif defined(BSD) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#elif defined(BSD) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__MirBSD__)
 #   define U_PLATFORM U_PF_BSD
 #elif defined(sun) || defined(__sun)
     /* Check defined(__SVR4) || defined(__svr4__) to distinguish Solaris from SunOS? */
@@ -268,6 +268,9 @@
 #elif U_PLATFORM == U_PF_SOLARIS
     /* Solaris has inttypes.h but not stdint.h. */
 #   define U_HAVE_STDINT_H 0
+#elif U_PLATFORM == U_PF_AIX && !defined(_AIX51) && defined(_POWER)
+    /* PPC AIX <= 4.3 has inttypes.h but not stdint.h. */
+#   define U_HAVE_STDINT_H 0
 #else
 #   define U_HAVE_STDINT_H 1
 #endif
@@ -283,6 +286,9 @@
 #elif U_PLATFORM == U_PF_SOLARIS
     /* Solaris has inttypes.h but not stdint.h. */
 #   define U_HAVE_INTTYPES_H 1
+#elif U_PLATFORM == U_PF_AIX && !defined(_AIX51) && defined(_POWER)
+    /* PPC AIX <= 4.3 has inttypes.h but not stdint.h. */
+#   define U_HAVE_INTTYPES_H 1
 #else
     /* Most platforms have both inttypes.h and stdint.h, or neither. */
 #   define U_HAVE_INTTYPES_H U_HAVE_STDINT_H
@@ -352,6 +358,9 @@
 #elif defined(_PA_RISC1_0) || defined(_PA_RISC1_1) || defined(_PA_RISC2_0)
     /* HPPA do not appear to predefine any endianness macros. */
 #   define U_IS_BIG_ENDIAN 1
+#elif defined(sparc) || defined(__sparc) || defined(__sparc__)
+    /* Some sparc based systems (e.g. Linux) do not predefine any endianness macros. */
+#   define U_IS_BIG_ENDIAN 1
 #else
 #   define U_IS_BIG_ENDIAN 0
 #endif