ndk_patches: add patches for sem and shm (#691)

[termux-packages] / README.md

diff --git a/README.md b/README.md
index c1386be..e5a45fe 100644 (file)
--- a/README.md
+++ b/README.md
@@ -122,6 +122,10 @@ Common porting problems
 * mempcpy(3) is a GNU extension. We have added it to <string.h> provided TERMUX_EXPOSE_MEMPCPY is defined,
   so use something like CFLAGS+=" -DTERMUX_EXPOSE_MEMPCPY=1" for packages expecting that function to exist.
 
+* Android uses a customized version of shared memory managemnt known as ashmem. Standard shm and semaphore libc
+  wrappers (semget(2), shmat(2) and others) aren't available. Direct syscalls can be used with
+  `CFLAGS+=" -DTERMUX_SHMEM_STUBS=1 -DTERMUX_SEMOPS_STUBS=1"`.
+
 dlopen() and RTLD_* flags
 =================================
 <dlfcn.h> originally declares