Fix Compiler Error Android pthread

[hajoha]

Version of iperf3 (or development branch, such as master or
3.1-STABLE) to which this pull request applies:

• 3.16 and following

Issues fixed (if any):

• Following Compiler Errors

1.725 /tmp/iperf/src/iperf_client_api.c:61:28: error: incompatible pointer to integer conversion passing 'void *' to parameter of type 'int' [-Wint-conversion]
1.725     pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
1.725                            ^~~~~~~~~~~~~~~~~~~~~
1.725 /tmp/iperf/src/iperf_pthread.h:13:31: note: expanded from macro 'PTHREAD_CANCEL_ENABLE'
1.725 #define PTHREAD_CANCEL_ENABLE NULL
1.725                               ^~~~
1.725 /opt/android-ndk/android-ndk-r26b/toolchains/llvm/prebuilt/linux-x86_64/lib/clang/17/include/stddef.h:89:16: note: expanded from macro 'NULL'
1.725 #  define NULL ((void*)0)
1.725                ^~~~~~~~~~
1.725 /tmp/iperf/src/iperf_pthread.h:16:32: note: passing argument to parameter 'state' here
1.725 int pthread_setcancelstate(int state, int *oldstate);
1.725                                ^
1.727 1 error generated.
1.730 make: *** [/opt/android-ndk/android-ndk-r26b/build/core/build-binary.mk:413: /tmp/obj/local/arm64-v8a/objs/iperf3.16/src/iperf_client_api.o] Error 1
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1.615 /tmp/iperf/src/iperf_pthread.c:16:19: error: call to undeclared function 'iperf_set_thread_exit_handler'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
1.615     if ((status = iperf_set_thread_exit_handler()) == 0) {
1.615                   ^
1.616 /tmp/iperf/src/iperf_pthread.c:31:5: error: call to undeclared library function 'memset' with type 'void *(void *, int, unsigned long)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
1.616     memset(&actions, 0, sizeof(actions)); 
1.616     ^
1.616 /tmp/iperf/src/iperf_pthread.c:31:5: note: include the header <string.h> or explicitly provide a declaration for 'memset'
1.617 2 errors generated.
1.619 make: *** [/opt/android-ndk/android-ndk-r26b/build/core/build-binary.mk:413: /tmp/obj/local/arm64-v8a/objs/iperf3.16/src/iperf_pthread.o] Error 1
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If I apply the changes, it compiles without a problem.

Brief description of code changes (suitable for use as a commit message):

• Reordering of functions, so that functions are declared before their usage

If you want to try it out yourself, here.
Building ENV:

ARG API_VERSION=31
ARG SDK_VERSION=4333796
ARG NDK_VERSION=r26b
ARG IPERF_VERSION=iperf-3.17.1

Feel free to close this PR if I made a mistake or missing something.

[hajoha]

I just saw their is already this PR, feel free to close then

[bmah888]

Thanks for the PR! We'll go with #1687 but this looks like a case where great minds think alike. :-)